Which of the following is the inverse of f(x)=4x-10?
a.) f(x)=x-10/4
b.) f(x)=x+10/4
c.) f(x)=4/x-10
d.) f(x)=4/x+10

Injective- (one-to-One)
so
Replace the f(x) with y 
10-4x
Interchange the variables
x=10-4y
Solv for y.
y= 5/2 - x/4
So solve for y and replace with f-1 (x).
and it equals 
f-1 (x)=5/2- x/4