Question

If f(x) and f^-1(x) are inverse functions of each other and f(x)=2x+5, what is f^-1(4)?

Answer 1

4.5

Explanation:

We are here given that ,

=> f(x) = 2x - 5

=> y = 2x - 5

Replace x and y with each other .

=> x = 2y - 5

solve for y ,

=> 2y = x +5

=> y = (x+5)/2

=> f-¹(x) = (x+5)/2

Now ,

=> f-¹(4) = 4+5/2 = 9/2 = 4.5