A piece of wire 4m long is cut into two pieces, then each pieces is bent into a square. Express the combined area one variable.?

Well it would be best to have this one variable describe the point on the wire where the cut occurred.
This means one wire has length x and the other has length 4-x.
Bending them into fourths gives you squares, so the length of one side on each is:
x/4 and (4-x)/4
To get area you take the square of these values to get:
Area1 = (x/4)^2 = x^2/16
Area2 = [(4-x)/4]^2 = (4 - x)^2/16
Combined area = Area1 + Area2 = [x^2 + (4-x)^2]/16