Which expression is NOT equivalent to x22x\frac{x^2}{2x}2xx2?
x22x\frac{x^2}{2x}2xx2
x32x2\frac{x^3}{2x^2}2x2x3
x2\frac{x}{2}2x
2x24x\frac{2x^2}{4x}4x2x2