[tex]\dfrac{4v^2}{wu+u^2} \times \dfrac{7w+7u}{4v-8v^2}\\\\\\=\dfrac{4v^2(7w+7u)}{(wu+u^2)(4v-8v^2)}\\\\\\=\dfrac{4v^2 \cdot 7(w+u)}{u(w+u)\cdot 4v(1-2v)}\\\\\\=\dfrac{7v}{u(1-2v)}[/tex]
