if f(a)=b then f⁻¹(b)=a
and if f⁻¹(a)=b then f(b)=a
this is helpful for our problem
alright
the problem is
find f⁻¹(2)
ok
f⁻¹(2)=?
look familiar?
if f⁻¹(2)=? then f(?)=2
easy now
so
solve for x such that f(x)=2
2=2x-6
8=2x
4=x
so te value is 4
f⁻¹(2)=4