College

Select the correct answer.

Solve:
[tex]$5|x+9|=80$[/tex]

A. [tex]$x=-7$[/tex] or [tex]$x=25$[/tex]
B. [tex]$x=-25$[/tex] or [tex]$x=7$[/tex]
C. [tex]$x=7$[/tex] or [tex]$x=16$[/tex]
D. [tex]$x=-25$[/tex] or [tex]$x=9$[/tex]

Answer :

To solve the equation [tex]\(5|x+9| = 80\)[/tex], we need to follow these steps:

1. Divide Both Sides by 5:

First, we simplify the equation by dividing both sides by 5:
[tex]\[
|x+9| = \frac{80}{5} = 16
\][/tex]

2. Consider Two Cases for the Absolute Value:

Since we have an absolute value equation [tex]\(|x+9| = 16\)[/tex], we need to consider two possible cases:

- Case 1: [tex]\(x+9 = 16\)[/tex]
- Case 2: [tex]\(x+9 = -16\)[/tex]

3. Solve Case 1:

For the equation [tex]\(x+9 = 16\)[/tex], we solve for [tex]\(x\)[/tex] by subtracting 9 from both sides:
[tex]\[
x = 16 - 9 = 7
\][/tex]

4. Solve Case 2:

For the equation [tex]\(x+9 = -16\)[/tex], we solve for [tex]\(x\)[/tex] by subtracting 9 from both sides:
[tex]\[
x = -16 - 9 = -25
\][/tex]

5. Write the Final Solution:

The solutions for the equation [tex]\(5 |x+9| = 80\)[/tex] are:
[tex]\[
x = 7 \quad \text{or} \quad x = -25
\][/tex]

So, the correct answer is B. [tex]\(x = -25\)[/tex] or [tex]\(x = 7\)[/tex].