F.2 maths (factorization) (20)

1. -(-x-2y)^2+4x^2
= (2x)^2 - (-x-2y)^2
= (2x - x - 2y) (2x + x + 2y)
= (x - 2y)(3x + 2y)

2. 75k-3k(2k-1)^2
= 3k [25 - (2k-1)^2]
= 3k [5^2 - (2k-1)^2]
= 3k (5 + 2k - 1)(5 - 2k + 1)
= 3k (2k + 4)(6 - 2k)
= 3k *2(k + 2) *2(3 - k)
= 12k (k + 2) (3 - k)

3. x^4-1
= (x^2)^2 - 1^2
= (x^2 - 1)(x^2 + 1)
= (x - 1)(x + 1)(x^2 + 1)

4.1+36c^2 d^2-4c^2 -9d^2
= (1 - 4c^2) + (36 c^2 d^2 - 9d^2)
= 1^2 - (2c)^2 + (9d^2) (4c^2 - 1)
= (1 - 2c)(1 + 2c) + (9d^2) (2c - 1)(2c + 1)
= (9d^2) (2c - 1)(2c + 1) - (2c - 1)(2c + 1)
= (2c - 1)(2c + 1) [(9d^2) - 1]
= (2c - 1)(2c + 1) [(3d)^2 - 1^2]
= (2c - 1)(2c + 1)(3d - 1)(3d + 1)

Can you tell me what is ^ first?