Question 1036668
If you mean {{{y=-4x-8x+5}}},
{{{-12x+5=0}}}
{{{12x=5}}}
{{{x=5/12}}}
.
.
If you mean {{{y=-4x^2-8x+5}}}
{{{y=-(2x-1)(2x+5)}}}
Then,
{{{2x-1=0}}}
{{{2x=1}}}
{{{x=1/2}}}
and
{{{2x+5=0}}}
{{{2x=-5}}}
{{{x=-5/2}}}