Question

Please Help me. I'm losing my mind.


Given that f(x)=4 x + 7 and g(x)=9 - x^2, calculate
(a) f o g(x) =
(b) g o f(x) =
for f[g(x)] i got 4x^2-72x+331
for g[f(x0] i got 58-16x^2+56x
both answers were wrong. I've been working on this problem for the last hour and I'm losing my mind. help please.

Answer 1

f[g(x)]= -16x^2-56y-40

Answer 2

g[f(x)]= 43-4y^2

Answer 3

where is that y coming from?

Answer 4

sorry i meant x

Answer 5

Thank you. is it possible you could show me the break down for the one where you have to input the 9-x^2 into the 4x+7 equation? I spent a lot of time trying to make it work and I just couldn't understand what steps i was missing

Answer 6

when you input 9-x^2 into 4x+7, you get 4(9-x^2)+7. you then simplify it to 36-4x^2+7 which equals 43-4x^2

Answer 7

thank you! I think I was making it much harder on myself and confusing myself at the same time.

Answer 8

sure anytime