7. 3x² - 5x - 12
3x² - 9x + 4x - 12
(3x + 4)(x - 3)
8. x² - 9
x² + 3x - 3x - 9
(x - 3)(x + 3)
9. 8x³ + 12x² - 2x - 3
(8x³ + 12x² - 2x - 3)
(4x² - 1)(2x + 3)
10. 12x² + 16x - 3
12x² + 18x - 2x - 3
(6x - 1)(2x + 3)
11. x² + 8x + 9
(x² + 9x - x + (-9))
(x - 1)(x + (-9))
Extra Credit: 3(x + y) + a(x + y)
3(x) + 3(y) + a(x) + a(y)
3x + 3y + ax + ay
3x + ax + 3y + ay
(3 + a)x + (3 + a)y