f(x)=6(x+2)-3 solve for the inverse function when x=21

Question

solve for the inverse when x=21      F(x)=6(x+2)-3

Answer 1

Hi Michele;

f(x)=6(x+2)-3

y=6x+12-3

y=6x+9

f(x)=f(21)=y

y=6(21)+9

y=126+9=135

 

y=6x+9

y-9=6x

(y-9)/6=x

x=(y-9)/6

f^-1(x)=f^-1(135)=x

x=(y-9)/6

x=(135-9)/6

x=126/6=21