differentiating f you get
8x-4a=0 at minimum
x=a/2
substitute a/2 for x in the polynomial f
a2-2a2+a2-2a+2=3
implies a=-1/2
so answer is 0
differentiating f you get
8x-4a=0 at minimum
x=a/2
substitute a/2 for x in the polynomial f
a2-2a2+a2-2a+2=3
implies a=-1/2
so answer is 0