Find the inverse of function f. f(x) = 1/2x +7 / [tex]f(x)=\frac{1}{2}x + 7[/tex]

A.) f^-1 (x) = x -7 / [tex]f^{-1}\:\left(x\right)\:=\:x\:-7\:\:[/tex]
B.) f^-1 (x) = 2x - 7 / [tex]\:f^{-1\:}\left(x\right)\:=\:2x\:-\:7[/tex]
C.) f^-1 (x) = 2x- 14 / [tex]\:f^{-1\:}\left(x\right)\:=2x-\:14[/tex]
D.) f^-1 (x) = 2x + 1/7 / [tex]f^{-1\:}\left(x\right)=2x\:+\:\frac{1}{7}\:[/tex]