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

Answer :

Sure, let's solve the equation [tex]\(5|x+9|=80\)[/tex] step by step.

1. Isolate the absolute value:

[tex]\[
|x+9| = \frac{80}{5} = 16
\][/tex]

2. Set up the cases for the absolute value equation:

When we have an equation with an absolute value, [tex]\( |x + 9| = 16 \)[/tex], it means that the expression inside can be either 16 or -16.

So we consider two separate cases:

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

3. Solve each case separately:

- Case 1:
[tex]\[
x + 9 = 16
\][/tex]
Subtract 9 from both sides:
[tex]\[
x = 16 - 9 = 7
\][/tex]

- Case 2:
[tex]\[
x + 9 = -16
\][/tex]
Subtract 9 from both sides:
[tex]\[
x = -16 - 9 = -25
\][/tex]

4. Write the set of solutions:

The values of [tex]\(x\)[/tex] that satisfy the equation [tex]\(5|x+9|=80\)[/tex] are [tex]\(x = 7\)[/tex] and [tex]\(x = -25\)[/tex].

Given the answer choices:

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

The correct answer is: D. [tex]\(x=-25\)[/tex] or [tex]\(x=7\)[/tex].