Question 907758
the vertex form of a Parabola opening up(a>0) or down(a<0), 
{{{y=a(x-h)^2 +k}}} where(h,k) is the vertex  and  x = h  is the Line of Symmetry
 f(x)=2x^2-8x+11 = 2(x{{{highlight_green(-2)}}})^2 {{{highlight_green(-8)}}}  + 11 = {{{2(x-2)^2 +3}}}
Completing Square for ax^2+bx+c, Note: b/2a = {{{(-8)/(2*2)}}}= -2 and {{{highlight_green(-8)}}}= (-)2(-2)^2
 f(x)=2(x-2)^2 + 3 ..... V(2,3) Quadrant I
{{{drawing(300,300,   -10,10,-10,10,  blue(line(2,10,2,-10))  ,  
 grid(1),
circle(2,3,0.4),
graph( 300, 300, -10,10,-10,10,0,2x^2-8x+11))}}}