Question 37981
The area of a square with sides equal to x is given by:
{{{A = x^2}}} Now if you remove a square of sides (x-3), the area of the removed square is given by: a = (x-3)^2, so the remaining area is:
{{{A-a = x^2-(x-3)^2}}} Let's call this area A1.
{{{A1 = x^2-(x^2-6x+9)}}} Simplify.
{{{A1 = 6x-9}}} This is the remaining area as a function of x.