URGENT (Pre-Cal) For f(x)=8x-7 and g(x)=x+7 / 8 find the following functions?

Question

A. (f * g)(x)=
B. (g * f)(x)=
C. (f * g)(8)=
D. (g * f)(8)=

I am taking my final exam for pre-cal RIGHT NOW. My average is 71. I'm pretty sure I'm going to pass but I'd love it if someone would help me out by giving me the answer or telling me how to solve this. It's a comprehensive final and I simply do not remember how to solve this from 4 months ago.

Loner · Answer

g(x)=x+7/8 you solve g(x) first by plugging in the x in for x. once you solve for x, then you plug in whatever you got for g(x), and substitute that in for f(x).

next one you would solve for f(x)(you're just solving 8x-7, not difficult) and whatever answer you got for that one, you plug in for g(x). so if you got like 5 when you solve f(x), then you would be solving g(5). in this case, it's g(8x+7)=x+7/8

then you would solve g(8) by plugging in 8 for x. 8+7/8. whatever you get for that: 1.9, you would plug in for f(1.9). 8(1.9)-7

this one, you would do the same:
f(8)=8x - 7
f(8)=8(8) - 7
f(8)=64 - 7
f(8) = 57
g(57)=x + 7 / 8
g(57)=(57) + 7 / 8
g(57)=64 / 8
(g * f)(x)=8

whichever function is closest to the (x), you solve first, then plug into the other one. good luck!!!

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URGENT (Pre-Cal) For f(x)=8x-7 and g(x)=x+7 / 8 find the following functions?

1 Answer