1 x2 + 7x + 12 = ________________________
 2 x2 - 3x - 10 = _________________________
 3 x2 - 25 = _________________________
 4 x2 - 100 = ________________________
 5 4x2 - 9 = _________________________
 6 16x2 - 121 = _________________________
 7 x2 + 6x - 24 = _________________________
 8 x2 - y2 = _________________________
 9 81 - x2 = _________________________
 10 36x2 - 100y2 = _________________________
 Factor each expression