To write an expression for the area A(x) of the playground in square meters as a function of the length x in meters of the side parallel to the wall, you can use the formula for the area of a rectangle:
A(x) = x * (length perpendicular to the wall)
If the length perpendicular to the wall is constant, say "w" meters, then the expression becomes:
A(x) = x * w
So, A(x) is a function of x and w, where x represents the length parallel to the wall, and w represents the constant length perpendicular to the wall.