If f(x) = 3x + 2, find f(f–1(14)).

Question

If f(x) = 3x + 2, find f(f–1(14)).

 

 

Thank you for your help 

Answer 1

f(x) = 3x + 2

x = 3f^-1(x) + 2

x - 2 = 3f^-1(x)

(x - 2)/3 = f^-1(x)

(14 - 2)/3 = f^-1(14)

12/3 = f^-1(14)

4 = f^-1(14)  

 

f(f^-1(14)) = f(4)

f(4) = 3(4) + 2

f(4) = 12 + 2

f(4) = 14

 

A function and its inverse are inverse operations, like addition and subtraction. They undo each other.

 

f(f^-1(x) = x