Exercises on Bhaskara's Formula

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Solve the list of exercises on Bhaskara's formula and clear your doubts with solved and commented exercises.

Bhaskara's Formula

x with 1 subscript equals numerator minus b space plus space square root of increment over denominator 2 space. space to end of fraction x with 2 subscript space equals space numerator minus b space minus space square root of increment over denominator 2 space. space at the end of the fraction

Where: increment equal to b squared space minus space 4 space. space to space. c space

The is the coefficient next to x squared,
B is the coefficient next to x,
ç is the independent coefficient.

Exercise 1

Using Bhaskara's formula, find the roots of the equation 2 x squared space minus space 7 x space plus space 3 space equals space 0.

Efficient space is two points a equals 2 b equals minus 7 c equals 3

Determining the delta

increment equal to b squared minus 4. The. c increment equals left parenthesis minus 7 right parenthesis squared minus 4.2.3 increment equals 49 space minus space 24 increment equals 25

Determining the roots of the equation
x with 1 subscript equals numerator minus left parenthesis minus 7 right parenthesis space plus space square root of 25 over denominator 2 space. space 2 end of fraction equals numerator 7 space plus space 5 over denominator 4 end of fraction equals 12 over 4 equals 3 x with 2 subscript equals numerator minus left parenthesis minus 7 right parenthesis space minus space square root of 25 over denominator 2 space. space 2 end of fraction equals numerator 7 space minus space 5 over denominator 4 end of fraction equals 2 over 4 equals 1 half

Exercise 2

The solution set that makes the equation x squared space plus space 5 x space minus 14 space equals space 0 true is

a) S={1.7}
b) S={3,4}
c) S={2, -7}.
d) S={4.5}
e) S={8,3}

Correct answer: c) S={2, -7}.

The coefficients are:
a = 1
b = 5
c = -14

Determining the delta
increment equal to b squared minus 4. The. c increment equals 5 squared minus 4.1. left parenthesis minus 14 right parenthesis increment equals 25 space plus space 56 increment equals 81

Using Bhaskara's formula

x with 1 subscript equals numerator minus 5 space plus space square root of 81 over denominator 2 space. space 1 end of fraction equals numerator minus 5 space plus space 9 over denominator 2 end of fraction equals 4 over 2 equals 2 x with 2 subscript equals the numerator minus 5 space minus space square root of 81 over denominator 2 space. space 1 end of fraction equals numerator minus 5 space minus space 9 over denominator 2 end of fraction equals numerator minus 14 over denominator 2 end of fraction equals minus 7

The solution set of the equation is S={2, -7}.

Exercise 3

Determine The Values ​​Of X That Satisfy The Equation left parenthesis 4 space minus space x parenthesis right parenthesis left parenthesis 3 space plus space x parenthesis right space equals space 0.

Using the distributive property of multiplication, we have:

left parenthesis 4 minus x right parenthesis left parenthesis 3 plus x right parenthesis equals 0 12 space plus space 4 x space minus 3 x space minus x squared equals 0 minus x squared plus x plus 12 equals 0

The terms of the quadratic equation are:

a = -1
b = 1
c = 12

Calculating the delta

increment equal to b squared minus 4. The. c increment equals 1 space minus space 4. left parenthesis minus 1 right parenthesis.12 increment equals 1 plus 48 increment equals 49

Using Bhaskara's formula to find the roots of the equation:

x with 1 subscript equals numerator minus b plus square root increment over denominator 2. the end of the fraction equals numerator minus 1 space plus square root of 49 over denominator 2. left parenthesis minus 1 right parenthesis end of fraction equals numerator minus 1 space plus space 7 over denominator minus 2 end of fraction equals numerator 6 over denominator minus 2 end of fraction equals minus 3 x with 2 subscript equals numerator minus b minus square root of increment over denominator 2. the end of the fraction equals numerator minus 1 space minus square root of 49 over denominator 2. left parenthesis minus 1 right parenthesis end of fraction equals numerator minus 1 space minus space 7 over denominator minus 2 end of fraction equals numerator minus 8 over denominator minus 2 end of equal fraction at 4

The values ​​of x that satisfy the equation are x = -3 and x = 4.

Exercise 4

Since the following equation of the second degree, 3 x squared space plus space 2 x space minus space 8 space equals 0, find the product of the roots.

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Correct answer: -8/3

Determining the roots of the equation using Bhaskara's formula.

The coefficients are:
a = 3
b = 2
c = -8

Delta
increment equal to b squared minus 4. The. c increment equals 2 squared minus 4.3. left parenthesis minus 8 right parenthesis increment equals 4 plus 96 increment equals 100

Calculation of roots

x with 1 subscript equals numerator minus b plus square root increment over denominator 2. end of fraction equals numerator minus 2 space plus square root of 100 over denominator 2.3 end of fraction equals numerator minus 2 space plus space 10 over denominator 6 end of fraction equals 8 over 6 equals 4 over 3 x with 2 subscript equals numerator minus b minus square root of increment over denominator 2. end of fraction equals numerator minus 2 space minus square root of 100 over denominator 2.3 end of fraction equals numerator minus 2 space minus space 10 over denominator 6 end of fraction equals numerator minus 12 over denominator 6 end of fraction equals minus 2

Determining the product between the roots.

x with 1 space subscript. space x with 2 subscript equals 4 over 3 multiplication sign left parenthesis minus 2 right parenthesis equals 4 over 3 sign of multiplication numerator minus 2 over denominator 1 end of fraction equals numerator minus 8 over denominator 3 end of fraction equals negative 8 about 3

Exercise 5

Classify equations that have real roots.

I right parenthesis space space x squared minus space x space plus 1 equals 0 I I right parenthesis space minus x squared plus 2 x plus 3 equals 0 I I I parenthesis right space 4 x to the power of 2 space end of exponential plus 6 x plus 2 equals 0 space I V right parenthesis x space squared over 2 plus 5 x space plus 12 equal space at 0

Correct answers: II and IV.

There are no real roots in equations with increment negative because in Bhaskara's formula it is the radicand of a square root, and there is no square root of negative numbers in real numbers.

I right parenthesis space space x squared minus space x space plus 1 equals 0 p a râ m e tr o s space a space equals space 1 b space equals space minus 1 c space equals space 1 increment equals b squared minus 4. The. c increment equals left parenthesis minus 1 right parenthesis squared minus 4.1.1 increment equals 1 minus 4 increment equals minus 3

Negative delta, so I has no real solution.

I I right parenthesis space minus x squared plus 2x plus 3 equals 0 a equals minus 1 b equals 2 c equals 3 increment equals b squared minus 4. The. c increment equals 2 squared minus 4. left parenthesis minus 1 right parenthesis.3 increment equals 4 plus 12 increment equals 16

Positive delta, therefore II has a real solution.

I I I right parenthesis space 4 x to the power of 2 space end of the exponential plus 6 x plus 2 equals 0 space a equals 4 b equals 6 c equals 2 increment equals b squared minus 4. The. c increment equals 6 squared minus 4.4.2 increment equals 36 space minus space 64 increment equals minus 28

Negative delta, so III has no real resolution.

I V right parenthesis x space squared over 2 plus 5 x space plus 12 space equals 0 a equals 1 half b equals 5 c equals 12 increment equals 5 squared minus 4.1 half.12 increment equals 25 space minus space 24 increment equals 1

Positive delta, therefore IV has a real solution.

Exercise 6

The following graph is determined by the function of the second degree x squared minus x space minus space c space equals space 0. The parameter c indicates the point of intersection of the curve with the y axis. The roots x1 and x2 are the real numbers that, when substituted into the equation, make it true, that is, both sides of the equality will be equal to zero. Based on the information and graph, determine parameter c.

Exercise Chart 6

Correct answer: c = -2.

objective
determine c.

Resolution

The roots are the points where the curve cuts the x-axis of the abscissa. So the roots are:

x with 1 subscript equals minus 1 space x with 2 subscript equals 2

The parameters are:

a space equals space 1 b space equals space minus 1

Bhaskara's formula is an equality that relates all these parameters.

x space equals numerator space minus b space plus or minus space square root of b squared minus 4. The. c end of the root over denominator 2. at the end of the fraction

To determine the value of c, just isolate it in the formula and, for this, we will arbitrate one of the roots, using the one with the highest value, therefore the positive value of the delta.

x with 2 subscript equals numerator minus b plus square root of b squared minus 4. The. c end of the root over denominator 2. at the end of the fraction
2. The. x with 2 subscript equals minus b plus square root of b squared minus 4. The. c end of root 2. The. x with 2 subscript space plus space b equals the square root of b squared minus 4. The. c end of the root

At this point, we square both sides of the equation to take the root of the delta.

left parenthesis 2. The. x with 2 subscript plus b right parenthesis squared equals left parenthesis square root of b squared minus 4. The. c end of root right parenthesis squared space left parenthesis 2. The. x with 2 subscript plus b right parenthesis squared equals space b squared minus 4. The. c left parenthesis 2. The. x with 2 subscript plus b right parenthesis minus b squared equals minus 4. The. c numerator left parenthesis 2. The. x with 2 subscript plus b right parenthesis minus b squared over denominator minus 4. the end of the fraction equal to c

Substituting the numeric values:

numerator left parenthesis 2. The. x with 2 subscript plus b right parenthesis minus b squared over denominator minus 4. the end of the fraction equals c numerator left parenthesis 2.1.2 minus 1 right parenthesis squared minus left parenthesis minus 1 right parenthesis squared over denominator minus 4.1 end of fraction equals c numerator left parenthesis 4 minus 1 right parenthesis squared minus 1 over denominator minus 4 end of fraction equals c numerator 3 squared minus 1 over denominator minus 4 end of fraction equals c numerator 9 minus 1 over denominator minus 4 end of fraction equals c numerator 8 over denominator minus 4 end of fraction equals c minus 2 equals to c

Thus, the parameter c is -2.

Exercise 7

(São José dos Pinhais City Hall - PR 2021) Tick the alternative that brings a correct statement of the largest of the solutions of the equation:

straight x squared space plus space 2 straight x space minus space 15 space equals space 0 space

a) It is unique.
b) It is negative.
c) It is a multiple of 4.
d) It is a perfect square.
e) It is equal to zero.

Correct Answer: a) It is odd.

Equation parameters:

a = 1
b = 2
c = -15

increment equal to b squared minus 4. The. c increment equals 2 squared minus 4.1. left parenthesis minus 15 right parenthesis increment equals 4 plus 60 increment equals 64
x with 1 subscript equals numerator minus 2 space plus space square root of 64 over denominator 2 end of fraction equals numerator minus 2 space plus space 8 over denominator 2 end of fraction equals 6 over 2 equals 3 x with 2 subscript equals numerator minus 2 space minus space square root of 64 over denominator 2 end of fraction equals numerator minus 2 space minus space 8 over denominator 2 end of fraction equals numerator minus 10 over denominator 2 end of fraction equals minus 5

Since the greatest solution of the equation, 3, is an odd number.

Exercise 8

(PUC - 2016)
Image associated with the resolution of the issue.

Consider a right triangle of hypotenuse a and legs b and c, with b > c, whose sides obey this rule. If a + b + c = 90, the value of a. c, yeah

a) 327
b) 345
c) 369
d) 381

Correct answer: c) 369.

The terms in parentheses are equivalent to the sides a, b, and c of the right triangle.

The statement also provides that a + b + c = 90, thus replacing the terms of the Pythagorean triad. In the case of a sum, the order does not matter.

a space plus space b space plus c space equals space 90 numerator m squared minus 1 over denominator 2 end of fraction plus m plus numerator m squared plus 1 over denominator 2 end of fraction equals 90 numerator m squared minus 1 over denominator 2 end of fraction plus numerator 2 m over denominator 2 end of fraction plus numerator m squared plus 1 over denominator 2 end of fraction equals 180 over 2 m squared minus 1 plus 2 m plus m squared plus 1 equals 180 2 m squared plus 2 m equals 180 2 m squared plus 2 m minus 180 equals 0 m squared plus m minus 90 equal to 0

Solving the quadratic equation to find m:

The coefficients are,
a = 1
b = 1
c = -90

increment equal to b squared minus 4. The. c increment equals 1 minus 4.1. left parenthesis minus 90 right parenthesis increment equals 1 plus 360 increment equals 361
m with 1 subscript equals numerator minus 1 plus square root of 361 over denominator 2.1 end of fraction equals numerator minus 1 plus 19 over denominator 2 end of fraction equals 18 over 2 equals 9 m with 2 subscript equals numerator minus 1 minus square root of 361 over denominator 2.1 end of fraction equals numerator minus 1 minus 19 over denominator 2 end of fraction equals numerator minus 20 over denominator 2 end of fraction equals minus 10

As it is a measure, we will disregard m2, as there is no negative measure.

Substituting the value 9 in the terms:

numerator m squared minus 1 over denominator 2 end of fraction equals numerator 9 squared minus 1 over denominator 2 end of fraction equals numerator 81 minus 1 over denominator 2 end of fraction equals 80 over 2 equals at 40
m space equals space 9
numerator m squared plus 1 over denominator 2 end of fraction equals numerator 9 squared plus 1 over denominator 2 end of fraction equals numerator 81 plus 1 over denominator 2 end of fraction equals 82 over 2 equals at 41

In a right triangle, the hypotenuse is the longest side, so a = 41. The smallest side is c, according to the statement, so c = 9.

In this way, the product is:

to space. space c space equals space 41 space. space 9 space equals space 369

Exercise 9

Bhaskara formula and spreadsheet

(CRF-SP - 2018) Bhaskara's formula is a method to find the real roots of a quadratic equation using only its coefficients. It is worth remembering that coefficient is the number that multiplies an unknown in an equation. In its original form, Bhaskara's formula is given by the following expression:

start style math size 18px x equals numerator minus b plus or minus square root of b squared minus 4. The. c end of the root over denominator 2. end of fraction end of style

Discriminant is the expression present within the root in Bhaskara's formula. It is commonly represented by the Greek letter Δ (Delta) and gets its name from the fact that it discriminates the results of a equation as follows: Mark the alternative that correctly transcribes the formula Δ = b2 – 4.a.c in the cell E2.

Table associated with the resolution of the question.

a) =C2*(C2-4)*B2*D2.

b) =(B2^B2)-4*A2*C2.

c) =POWER(C2;2)-4*B2*D2.

d) =POWER(C2;C2)-4*B2*D2.

Correct answer: c) =POWER(C2;2)-4*B2*D2.

The delta equation must be entered in cell E2 (column E and row 2). Therefore, the parameters are all from line 2.

In a spreadsheet every formula starts with the equal symbol =.

Since the delta equation starts with b squared, in the worksheet, the formula of having a power, thus, we discard options a) and b).

In the worksheet, the parameter b is in cell C2, and it is the value that is in this cell that must be squared.

The construction of the power function in a spreadsheet looks like this:

1) To call the power function, type: =POWER

2) The base and the exponent follow immediately, in parentheses, separated with a semicolon ;

3) First the base, then the exponent.

So the function is:

equals P O T E N C I A left parenthesis C 2 semicolon 2 right parenthesis minus 4 asterisk B 2 asterisk D 2

Study more with:

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Read too:

  • Bhaskara's Formula
  • Quadratic Function
  • Vertex of the Parabola
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