To find the inverse of a function, stick a y for the f(x).
So, f(x) = 4x + 12 becomes y = 4x + 12
Then switch the x and y.
So, y = 4x + 12 becomes x = 4y + 12
Then solve for y.
x = 4y + 12
x - 4y = 12 <-- Subtract both sides by 4y
-4y = 12 - x <-- Subtract both sides by x
y =
So, the inverse of f(x) is g(x) = -3 + x/4.
So, f(x) = 4x + 12 becomes y = 4x + 12
Then switch the x and y.
So, y = 4x + 12 becomes x = 4y + 12
Then solve for y.
x = 4y + 12
x - 4y = 12 <-- Subtract both sides by 4y
-4y = 12 - x <-- Subtract both sides by x
y =
So, the inverse of f(x) is g(x) = -3 + x/4.