Question 547063
Find the vertex, the line of symmetry, the maximum or minimum value of the quadratic function, and graph the function. 
f(x)=-2x^2+2x+4
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Standard form of equation for a parabola which opens downwards: y=-A(x-h)^2+k, (h,k) being the (x,y) coordinates of the vertex
f(x)=-2x^2+2x+4
complete the square
f(x)=-2(x^2-x+1/4)+4+1/2
f(x)=-2(x-1/2)^2+9/2
A=-2
vertex(1/2,9/2)
line or axis of symmetry: x=1/2
maximum value: 9/2
see graph below as a visual check on the above:
{{{ graph( 300, 300, -10, 10, -10, 10,-2(x-1/2)^2+9/2) }}}