How do you write y= -4x^2+8x-1 into vertex form?

1 Answer
May 23, 2015

General vertex form for a parabolic equation is
y=m(x-a)^2 +b
where the vertex is at (a,b)

Given y =-4x^2+8x-1

Extract m
y = (-4)(x^2-2x) -1

Complete the square
y=color(blue)((-4))(x^2-2xcolor(blue)(+1)) - 1 color(blue)(+4)

y= (-4)(x-1)+3
is in vertex form (with the vertex at (1,3))