Chapter 9.4, Problem 36PPS

To determine

Find the solutions.

Answer to Problem 36PPS

  $a=-9$ or $a=3$

Explanation of Solution

Given Information: $3a^2+18a=81$

Formula Used : Factorization Method

Calculation:

  $3a^2+18a=81$

So,

  $3a^2+18a-81=0$

Now, to make coefficient of $a^2$ = 1, divide the equation by 3.

  $a^2+6a-27=0$

Now, by factorization method

  $a^2+9a-3a-27=0$

So, simplify

  $a\left(a+9\right)-3\left(a+9\right)=0$

Now,

  $\left(a+9\right)(a-3)=0$

Now, compare equation with respect to 0.

  $\left(a+9\right)=0$ or $\left(a-3\right)=0$

Hence,

  $a=-9$ or $a=3$