Question

Which is the inverse of the function f(x) = x^2 − 4?

Answer 1

f(x) = x^2 - 4

Replace f(x) with y

y = x^2 - 4

Switch x and y.

x = y^2 - 4

Solve for y.

Add 4 to both sides.

x + 4 = y^2

√ both sides.

√(x + 4) = y

Switch sides, and replace y with f^-1(x)

f^-1(x) = √(x + 4)