alrighty, a hack I will hsow you
if f(a)=b then f⁻¹(b)=a
and
if f⁻¹(a)=b then f(b)=a
so we want to find f⁻¹(5)=?
well, by the above 'hack', if f⁻¹(5)=z then f(z)=5
find what value of x will make f(x)=5
[tex]5=\frac{x-1}{2}[/tex]
times 2 both sides
10=x-1
add 1
11=x
the answer is 11
