For finding the inverse of a function you have to write it as an ecuation.
[tex]y = 4x + 7[/tex]
Invert the values of x and y.
[tex]x = 4y + 7[/tex]
Our objetive now in this new equation is to clear y. First, subtract 7 in both sides of the equation.
[tex]x - 7 = 4y[/tex]
Then, divide both sides by 4.
[tex] \frac{x - 7}{4} = y[/tex]
Finally, invert the values of x and y again and put the equation like a function.
[tex] {f}^{ - 1} (x) = \frac{x - 7}{4} [/tex]
This is correct because f(x) = x is the axis of symmetry for both functions (green one).
