1.)Find inverse function of the function

f(x)=(x+3)+9

2.)Find the inverse of the function
r(x)=3x-6/5x+3

thanks

y = (x+3)+9 = x+12

x = y-12

y = (3x-6)/(5x+3)
5xy+3y = 3x-6
(5y-3)x = -6-3y
x = -(3y+6)/(5y-3)