Answer
$w=\displaystyle \frac{8}{5}$
Work Step by Step
$ 25w^{2}=80w-64\qquad$...add $-80w+64$ to both sides of the expression.
$ 25w^{2}-80w+64=0\qquad$...recognize a perfect square trinomial.
$(A\pm B)^{2}=A^{2}\pm 2AB+B^{2}$
$(5w-8)^{2}=0$
$(5w-8)(5w-8)=0\qquad$...apply the principle of zero products.
$5w=8$
$w=\displaystyle \frac{8}{5}$
Type the equation into a graphing utility and see
that the graph intercepts the x-axis at $\displaystyle \frac{8}{5}$.
