Question 106110
Look at this part of the discussion when you multiplied the factors together. 
{{{y=2.87(x+1)(x-0.67)}}}
Use the FOIL method (First Outer Inner Last)
{{{(x+1)(x-0.67)=x*x+x*(-0.67)+(1)x+(1)(-0.67)}}}
{{{(x+1)(x-0.67)=x^2+x*highlight((1-0.67))-0.67}}}
{{{(x+1)(x-0.67)=x^2+highlight(0.33)x-0.67}}}
I hope this answers your question.