SOLUTION: 19. f(x) = 15x + 12 g(x) = -10x + 15 find f(g(8)) A. 639 B. -963 C. 178031 D. -5943 E. -524 F. -68203

Algebra ->  Functions -> SOLUTION: 19. f(x) = 15x + 12 g(x) = -10x + 15 find f(g(8)) A. 639 B. -963 C. 178031 D. -5943 E. -524 F. -68203      Log On


   

Question 1197811: 19. f(x) = 15x + 12
g(x) = -10x + 15
find f(g(8))
A. 639
B. -963
C. 178031
D. -5943
E. -524
F. -68203
Found 2 solutions by MathLover1, ikleyn:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

f%28x%29+=+15x+%2B+12
g%28x%29+=+-10x+%2B+15

find f%28g%288%29%29
first find f%28g%28x%29%29
f%28g%28x%29%29=f%28-10x+%2B+15%29
f%28g%28x%29%29=15%28-10x+%2B+15%29%2B12
f%28g%28x%29%29=-150x+%2B+225%2B12
f%28g%28x%29%29=-150x+%2B+237
then
f%28g%288%29%29=-150%2A8+%2B+237
f%28g%288%29%29=-1200+%2B+237
f%28g%288%29%29=-963

answer: B. -963


Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
.

It is a two-steps problem.

Solve it in two steps.

As the first step, calculate g(8).

As the second step, substitute the value g(8) into the formula for f(x) instead of x and calculate the answer.