You can 
put this solution on YOUR website!  
Hi
vertex form of a parabola,  where(h,k) is the vertex
 where(h,k) is the vertex
f(x)=-2x^2-4x-3
f(x)=-2[x^2+2x + 3/2]
f(x)=-2[x^2+2x +1  -1 +3/2]
f(x)=-2[(x+1)^2   -1 +3/2]
f(x)=-2(x+1)^2  -2( -1 +3/2)
f(x)=-2(x+1)^2 + 2 - 3
f(x)=-2(x+1)^2 -1 
(-1, -1) is the vertex 
