College

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 :

Certainly! Let's solve the equation [tex]\( f(x) = 15 \)[/tex] for the given function [tex]\( f(x) = 4|x - 5| + 3 \)[/tex].

We start with the equation:
[tex]\[ f(x) = 4|x - 5| + 3 \][/tex]

We want to find where [tex]\( f(x) = 15 \)[/tex], so we set the equation equal to 15:
[tex]\[ 4|x - 5| + 3 = 15 \][/tex]

Next, we subtract 3 from both sides to isolate the absolute value term:
[tex]\[ 4|x - 5| = 12 \][/tex]

Then, we divide both sides by 4:
[tex]\[ |x - 5| = 3 \][/tex]

The absolute value equation [tex]\( |x - 5| = 3 \)[/tex] gives us two possible equations to solve:

1. [tex]\( x - 5 = 3 \)[/tex]
2. [tex]\( x - 5 = -3 \)[/tex]

Now, let's solve these equations one by one:

1. For [tex]\( x - 5 = 3 \)[/tex]:
[tex]\[ x = 3 + 5 \][/tex]
[tex]\[ x = 8 \][/tex]

2. For [tex]\( x - 5 = -3 \)[/tex]:
[tex]\[ x = -3 + 5 \][/tex]
[tex]\[ x = 2 \][/tex]

So, the values of [tex]\( x \)[/tex] that satisfy [tex]\( f(x) = 15 \)[/tex] are:
[tex]\[ x = 2 \quad \text{and} \quad x = 8 \][/tex]

Thus, the correct answer is:
[tex]\[
\boxed{x=2, x=8}
\][/tex]

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