[tex]15 + \sqrt{5x - 5} = f(x)[/tex]
Replace y for x and vice versa
[tex]15 + \sqrt{5y - 5} = x[/tex]
Solve for y.
[tex]15 + 5y - 5 = {x}^{2} [/tex]
[tex]15 + 5y = {x}^{2} + 5[/tex]
[tex]5y = {x}^{2} - 10[/tex]
[tex]y = \frac{ {x}^{2} - 10 }{5} [/tex]
[tex]f {}^{ - 1} (x) = \frac{ {x}^{2} - 10 }{5} [/tex]
If
