Let’s study carefully, the following tricky ways of factorisation.

$x^2 + 5x + 6 = (x + 2)(x + 3)$

(where $2 + 3 = 5$ and $2 times 3 = 6$)

$x^2 – 5x + 6 = (x – 2)(x – 3)$

(where $-2 – 3 = -5$ and $-2 times (-3) = 6$)

$x^2 + x – 6 = (x – 2)(x + 3)$

(where $-2 + 3 = 1$ and $-2 times 3 = -6$)

$x^2 – x – 6 = (x + 2)(x – 3)$

(where $2 – 3 = -1$ and $2 times (-3) = -6$)

Now, let’s apply the tricky ways of factorization. Say and write the answers as quickly as possible.

a) $x^2 + 3x + 2 =$ ………………..

(where $1 + 2 = 3$ and $1 times 2 = 2$)

b) $x^2 – 3x + 2 =$ ………………..

(where $-1 – 2 = -3$ and $-1 times (-2) = 2$)

c) $x^2 + x – 2 =$ ………………..

(where $2 – 1 = 1$ and $2 times (-1) = -2$)

d) $x^2 – x – 2 =$ ………………..

(where $-2 + 1 = -1$ and $-2 times 1 = -2$)

e) $x^2 + 9x + 20 =$ ………………..

f) $x^2 – 9x + 20 =$ ………………..