High School

If [tex]f(x) = \frac{2}{3} x + 9x[/tex], what is the value of [tex]f(12)[/tex]?

A. 116
B. 108
C. 70
D. 94

Answer :

Let's solve this problem step-by-step:

We need to find the value of the function [tex]\( f(x) \)[/tex] when [tex]\( x = 12 \)[/tex]. The function is given by:

[tex]\[ f(x) = \frac{2}{3}x + 9x \][/tex]

First, let's combine the terms:

1. Notice that [tex]\(\frac{2}{3}x + 9x\)[/tex] can be rewritten by factoring out [tex]\(x\)[/tex]:

[tex]\[ f(x) = \left( \frac{2}{3} + 9 \right)x \][/tex]

2. Simplify the expression inside the parentheses:

[tex]\[ \frac{2}{3} + 9 = \frac{2}{3} + \frac{27}{3} = \frac{2 + 27}{3} = \frac{29}{3} \][/tex]

So, the function simplifies to:

[tex]\[ f(x) = \frac{29}{3}x \][/tex]

Now, substitute [tex]\( x = 12 \)[/tex] into this simplified expression:

[tex]\[ f(12) = \frac{29}{3} \times 12 \][/tex]

Calculate this product:

[tex]\[ f(12) = \frac{29 \times 12}{3} \][/tex]

[tex]\[ f(12) = \frac{348}{3} \][/tex]

[tex]\[ f(12) = 116 \][/tex]

Therefore, the value of [tex]\( f(12) \)[/tex] is 116, which corresponds to option (a).