Factories:

x(a – 3) + y(3 – a)

12

Factories:

2a + 6b – 3(a + 3b)²

13

Factories:

16(2p – 3q)² – 4(2p – 3q)

15

Factories:

12(2x – 3y)² – 16(3y – 2x)

16

Factories:

(x + y)(2x + 5) – (x + y)(x + 3)