SOLUTION: What is the value of g(x) - f(x) if: f(x) = 2x + 4 g(x) = 3x - 2 x = 12?

Algebra ->  Functions -> SOLUTION: What is the value of g(x) - f(x) if: f(x) = 2x + 4 g(x) = 3x - 2 x = 12?      Log On


   

Question 423357: What is the value of g(x) - f(x) if:
f(x) = 2x + 4
g(x) = 3x - 2
x = 12?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
g(x) = 3x - 2
f(x) = 2x + 4
x = 12

g-f(x) = g(x) - f(x) = (3x-2) - (2x+4)

this becomes 3x - 2 - 2x - 4 which becomes x - 6

when x = 12, this becomes 12 - 6 = 6

an alternative way to solve this is to solve for x = 12 first and then do the f(x) - g(x) thing.

example:

your original problem:

g(x) = 3x - 2
f(x) = 2x + 4
x = 12

replace x with 12 in f(x) and g(x) to get:

g(12) = 3*12 - 2 = 36 - 2 = 34
f(x) = 2*12 + 4 = 24 + 4 = 28

g(12) - f(12) = 34 - 28 = 6