Inverse

Problem:



Solution:

It is easy to find the inverse first

Let $y = 5x - 3$, we solve for $x$ give $x = \frac{y + 3}{5}$, that is the inverse.

The rest is just value substitution exercise.

a) $f^{-1}(8) = \frac{8 + 3}{5} = \frac{11}{5}$
b) $f^{-1}(y) = 17$ implies $y = f(17) = 5 \times 17 - 3 = 82$.
c) This is trivial, $b = 1$.
d) And so is this, the answer is 103.