Question 76530
{{{y  =  x^2 - 6x + 8}}}
{{{y - 8 =  x^2 - 6x}}} Subtract 8 from both sides
{{{y - 8 + (-6/2)^2 =  x^2 - 6x+(-6/2)^2}}} Add {{{(-6/2)^2}}} to both sides. This will complete the square.
{{{y - 8 + 9 =  x^2 - 6x + 9}}}
{{{y + 1 =  (x-3)^2 }}} Factor the right side
{{{y =  (x-3)^2 -1 }}} Subtract 1 from both sides. This is the equation in {{{y = a(x - h)^2 + k}}} form where a=1, h=3, and k=-1.