Factorise

1)

x^{2} + 3 x + 2

(x + 1) (x + 2)

2)

x^{2} + 5 x + 6

(x + 2) (x + 3)

3)

x^{2} + 3 x - 4

(x + 4) (x - 1)

4)

x^{2} - 2 x - 15

(x + 3) (x - 5)

5)

x^{2} - 5 x + 6

(x - 3) (x - 2)

6)

x^{2} - 9 x + 20

(x - 4) (x - 5)

7)

x^{2} + x + \frac{2}{9}

(x + \frac{1}{3}) (x + \frac{2}{3})

8)

x^{2} + (2 \sqrt{3}) x + 3

(x + \sqrt{3}) (x + \sqrt{3})