Question 256357
Complete the square.
{{{y=-2x^2-4x + 2}}}
{{{y=-2(x^2+2x) + 2}}}
{{{y=-2(x^2+2x+1) + 2+2}}}
{{{y=-2(x+1)^2+4}}}
Axis of symmetry is x=-1.
When x=-1, y=4, the vertex is (-1,4).
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{{{drawing( 300, 300, -5, 5, -5, 5,grid( 1 ),green(line(-1,20,-1,-20)),circle( -1, 4, .2 ), graph( 300, 300, -5, 5, -5, 5, -2x^2-4x + 2)) }}}