Question 804691
to do so you need to complete the square
{{{y=2x^2+4x}}}
{{{y=2(x^2+2x)}}}
{{{y=2(x^2+2x+1-1)}}}
{{{y=2(x+1)^2-2}}}
the vertex is (-1,-2)
{{{graph( 400, 400, -10, 10, -10, 10, 2x^2+4x)}}}