If f(x)=2x+3 what is f-1(x)?

Question

If f(x)=2x+3 what is f-1(x)?

Answer 1

f^-1(x) is the inverse of f(x), which can be found by switching x and y and solving for y:

f(x) = 2x + 3

y = 2x + 3

x = 2y + 3

x - 3 = 2y

1/2x - 3/2 = y

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