Question

If f is an invertible function, defined as f(x)=3x-4/5, write f^-1(x).

Answer 1

$f(x) = 3x - \frac{4}{5} \\ 3x = f(x) + \frac{4}{5} = \frac{5f(x) + 4}{5} \\ x = \frac{5f(x) + 4}{15} \\ therefore \\ {f}^{ - 1} (x) = \frac{5x+ 4}{15}$