Question 550114
2x^2 -8x+7
=2(x^2 -4x) +7
= 2(x^2 -4x +4 -4) +7
= 2(x^2 -4x +4) -8+7
= 2(x-2)^2 -1
when x=2
.
its 2(0)^2 -1
= -1
so, -1 is the minimum value of this.