Question 172427
{{{y = 2(x+4)(x+2)}}} To find the x-intercepts, set y equal to zero.
{{{2(x+4)(x+2) = 0}}} so...
{{{(x+4)(x+2) = 0}}}, therefore, the x-intercepts are...
{{{x = -4}}} and  {{{x = -2}}} 
The x-coordinate of the vertex is found by:
{{{x = -b/2a}}} Expand the given equation by multiplying the factors:
{{{y = 2(x^2+6x+8)}}}
{{{y = 2x^2+12x+16}}} so a = 2 and b = 12, then,
{{{x = -b/2a}}} = {{{-12/2(2) = -3}}} Substitute into the original equation to find the y-coordinate.
{{{y = 2(-3+4)(-3+2)}}}
{{{y = 2(1)(-1)}}}
{{{y = -2}}}
The vertex is at (-3, -2)
{{{graph(400,400,-5,5,-5,5,2x^2+12x+16)}}}