Chapter 10: Q 10.57 (page 1186)

Solve the equation using quadratic formula.
$a^{2} - 2 a - 15 = 0$

Short Answer

Expert verified

The roots are $a = - 3, a = 5$

Step by step solution

Given Information.

The given equation is $a^{2} - 2 a - 15 = 0$ .

Write the quadratic equation in standard form and identify a,b,c.

$a^{2} - 2 a - 15 = 0$

The equation is in standard form.

So,

$a = 1, b = - 2, c = - 15$

Substitute the values in quadratic formula.

$a = \frac{- (- 2) \pm \sqrt{(- 2)^{2} - 4 (1) (- 15)}}{2 (1)} a = \frac{2 \pm \sqrt{4 + 60}}{2} a = \frac{2 \pm \sqrt{64}}{2}$

Use square root property.

$a = \frac{2 \pm 8}{2}$

Rewrite to show two solutions.

$a_{1} = \frac{2 + 8}{2} a_{1} = \frac{10}{2} a_{1} = 5$

and

$a_{2} = \frac{2 - 8}{2} a_{2} = \frac{- 6}{2} a_{2} = - 3$

Thus, the roots are $a = - 3, a = 5$ .

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Solve the equation using quadratic formula.
$a^{2} - 2 a - 15 = 0$

Short Answer

Step by step solution

Given Information.

Write the quadratic equation in standard form and identify a,b,c.

Substitute the values in quadratic formula.

Use square root property.

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Solve the equation using quadratic formula. a2-2a-15=0

Short Answer

Step by step solution

Given Information.

Write the quadratic equation in standard form and identify a,b,c.

Substitute the values in quadratic formula.

Use square root property.

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Math Textbooks

Mechanics Maths

Statistics

Probability and Statistics

Decision Maths

Calculus

Logic and Functions

Study anywhere. Anytime. Across all devices.

Solve the equation using quadratic formula.
$a^{2} - 2 a - 15 = 0$