The side of a square is x, and the area is a. express a in terms of x.

A = x^2

Each side is x, so the area is

area = length*width = x*x = x^2

Squaring a value is the same as multiplying it with itself

example: 5 squared = 5^2 = 5*5 = 25

it would be 6xy and -16xy.