x² - 3x - 10 = 0
(x - 5)(x + 2) = 0
x - 5 = 0 ⇒ x = 5
x + 2 = 0 ⇒ x = -2
(x - 5)(x + 2) = 0
x(x + 2) - 5(x + 2) = 0
x² + 2x - 5x - 10 = 0
x² - 3x - 10 = 0
x² ⇒ is x * x
Factors of 10 are:
1 x 10
2 x 5
-3 is indicative whether the factors will use a positive or negative sign.
to produce -3 the factors of 10 will be 2 and -5.
