Question

Let f(x) = 2x - 6. Solve f-1(x) when x = 2.

Answer 1

$f(x) = 2x - 6 \\\\ ff^{-1}(x) = 2f^{-1}(x) - 6 \\\\ x = 2f^{-1}(x) - 6 \\\\ \implies f^{-1}(x) = \frac{x + 6}{2} \\\\\\ f^{-1}(2) = \frac{2 + 6}{2 } = \frac{8}{2} = \boxed{4}$