(a) x + y
\((x^\frac32-xy^\frac12+x^\frac12y-y^\frac32)\)
= \(x(x^\frac12-y^\frac12) + y(x^\frac12-y^\frac12)\)
= (x + y) \((x^\frac12-y^\frac12)\)
∴ \((x^\frac32-xy^\frac12+x^\frac12y-y^\frac32)\) ÷ \((x^\frac12-y^\frac12)\)
= \(\frac{(x + y)(x^\frac12-y^\frac12)}{x^\frac12-y^\frac12}\) = (x + y)