One of the factors of (25x² - 1) + (1 + 5x)² is

1. 5 + x

2. 5 - x

3. 5x - 1

4. 10x

Factorisation of x² - 4x - 12 is

1. (x + 6)(x - 2)

2. (x - 6)(x + 2)

3. (x - 6)(x - 2)

4. (x + 6)(x + 2)

Factorisation of 4x² + 8x + 3 is

1. (x + 1)(x + 3)

2. (2x + 1)(2x + 3)

3. (2x + 2)(2x + 5)

4. (2x - 1)(2x - 3)

Factorisation of 16x² + 40x + 25 is

1. (4x + 5)(4x + 5)

2. (4x + 5)(4x - 5)

3. (4x - 5)(4x - 5)

4. (4x + 5)(4x + 7)