High School

Given the function [tex]f(x) = 4|x-5| + 3[/tex], for what values of [tex]x[/tex] is [tex]f(x) = 15[/tex]?

A. [tex]x = 2, x = 8[/tex]
B. [tex]x = 1.5, x = 8[/tex]
C. [tex]x = 2, x = 7.5[/tex]
D. [tex]x = 0.5, x = 7.5[/tex]

Answer :

Let's solve the equation step-by-step:

We are given the function [tex]\( f(x) = 4|x - 5| + 3 \)[/tex]. We need to find the values of [tex]\( x \)[/tex] that make [tex]\( f(x) = 15 \)[/tex].

1. Set up the equation:

[tex]\[
4|x - 5| + 3 = 15
\][/tex]

2. Subtract 3 from both sides:

[tex]\[
4|x - 5| = 12
\][/tex]

3. Divide both sides by 4:

[tex]\[
|x - 5| = 3
\][/tex]

4. Solve the absolute value equation:

The equation [tex]\( |x - 5| = 3 \)[/tex] means that [tex]\( x - 5 \)[/tex] can be 3 or -3.

- Case 1: [tex]\( x - 5 = 3 \)[/tex]

Solve for [tex]\( x \)[/tex]:

[tex]\[
x = 3 + 5 = 8
\][/tex]

- Case 2: [tex]\( x - 5 = -3 \)[/tex]

Solve for [tex]\( x \)[/tex]:

[tex]\[
x = -3 + 5 = 2
\][/tex]

5. Solution:

The solutions are [tex]\( x = 2 \)[/tex] and [tex]\( x = 8 \)[/tex].

Therefore, the correct answer is [tex]\( x = 2, x = 8 \)[/tex].