i have two problems that i need help with real quick if someone could please help me...

the first is..

1. Let A=B=C=R, and let f:A-->B, g:B-->C be define by f(a)=a^2-3a+5 and g(b)=2b+4. Find:

a) (f o g)(3)

b) (g o f)(x)

the second problem is:

2. f(x)=4x-8. Find f^-1.

Thanks for anyone that can help!!!!

~Rich