X2 - 4X - 5 = 0 easy factor, what two factors of - 5 add up to - 4 (X + 1)(X - 5) X = - 1 ------------- X = 5 --------------
4x + 20
7
x2 - 4x - 21 = (x-7)(x+3)
13
4x2 - 9 = (2x + 3)(2x - 3)
X2 - 4X - 5 = 0 easy factor, what two factors of - 5 add up to - 4 (X + 1)(X - 5) X = - 1 ------------- X = 5 --------------
x2-10 = 4x+11 x2-4x-10-11 = 0 x2-4x-21 = 0 (x+3)(x-7) = 0 x = -3 and x = 7
16
7x2 -4x -5x2 +2x = 2x2 -2x
(4x-5)(4x+5)
4x + 20
-4x-6x = -20 -10x = -20 Divide both sides by -10 rembering that a minus divided into a minus the result is positive: x = 2
7
-x2+2x
x2 - 4x - 21 = (x-7)(x+3)
4x times 4x equals 16x2.