Question 256317
First, use the FOIL method.
{{{(x-1)(x+6)=x^2+6x-x-6}}}
{{{(x-1)(x+6)=x^2+5x-6}}}
{{{(x-1)(x+6)=x^2+5x-6}}}
Then complete the square. 
Don't worry about the 2 multiplier, we'll put it in later.
{{{(x-1)(x+6)=x^2+5x+(5/2)^2-(5/2)^2-6}}}
{{{(x-1)(x+6)=(x+5/2)^2-(25/4)-(24/4)}}}
{{{(x-1)(x+6)=(x+5/2)^2-(49/4)}}}
Now put it the 2.
{{{2(x-1)(x+6)=2(x+5/2)^2-(49/2)}}}
{{{ graph( 300,300, -10, 10, -10, 10, 2(x-1)(x+6), 2(x+5/2)^2-(49/2)) }}}