The horizontal line test is used to determine if a functions inverse will be a function. You will compose the functions (that is, plug x into one function, plug that function into the inverse function, and then simplify) and verify that you end up with just "x". Here's what it looks like: Determine algebraically whether f (x) = 3x – 2 and g(x) = (x + 2)/3 are inverses of each other.
Use the horizontal line test to determine if a function is a one-to-one function.
If ANY horizontal line intersects your original function in ONLY ONE location, your function will be a one-to-one function and its inverse will also be a function.
