Posted by sherry on Tuesday, April 3, 2012 at 4:14pm.
9 x ^ 2 + 5 x - 4 + ( - 8 x ^ 2 + 9 x - 9 ) = 9 x ^ 2 + 5 x - 4 - 8 x ^ 2 + 9 x - 9 = 9 x ^ 2 - 8 x ^ 2 + 5 x + 9 x - 4 - 9 = x ^ 2 + 14 x - 13