Answer
$y=-\displaystyle \frac{5}{2}$
Work Step by Step
$ 4y^{2}+20y+25=0\qquad$...recognize a perfect square trinomial.
$(A\pm B)^{2}=A^{2}\pm 2AB+B^{2}$
$(2y+5)^{2}=0$
$(2y+5)(2y+5)=0\qquad$...apply the principle of zero products.
$2y=-5$
$y=-\displaystyle \frac{5}{2}$
Type the equation into a graphing utility and see
that the graph intercepts the x-axis at $-\displaystyle \frac{5}{2}$.
