Question

Factorise the following:

a) x² + 11x + 18
b) x² - 13x + 36
c) x² - 6x-27
d) x² + x-72
Answer
Answer
Answer
Answer

Answer 1

a) x = -9, -2

b) x = 9, 4

c) x = -9,8

Explanation:

a) x^2 + 11x + 18

9+2 = 11 and 9*2 = 18

(x + 9 )(x+2)

x + 9 = 0 and x +2 = 0

x = -9 and x = -2

b) x^2 - 13x + 36

-9 * -4 = 36 and -9 + (-4 ) = - 13

(x -9)(x-4) = 0
x = 9, 4

c) x^2 - 6 - 27

-9 * 3 = 27 and -9 + 3 = -6

(x -9) (x+3)

x = 9, -3

d) x^2 + x - 72

-8 * 9 = 72 and -8 + 9 = 1

(x +9) (x - 8)

x = -9, 8