Question

Let f(x) = 5x + 12. Find f−1(x).

A: 12x + 5
B: 1 over quantity 5 x plus 12
C: 5 over quantity x minus 12
D: quantity of x minus 12 over 5

Answer 1

`f(x)=5x+12 \\ \\ \hbox{solve for x:} \\ y=5x+12 \\ y-12=5x \\ x=(y-12)/(5) \\ \\ \hbox{swap x and y:} \\ y=(x-12)/(5) \\ \\ \boxed{f^(-1)(x)=(x-12)/(5)}`

The answer is D.