## Algebra: A Combined Approach (4th Edition)

$x^{2} + 7x + 12$ To factor this, we need two factors of 12 such that their sum is 7. Thus the factors are 4 and 3. $x^{2} + 7x + 12$ = $x^{2} + 3x + 4x + 12$ =x(x + 3) + 4(x + 3) = (x + 4)(x + 3) .