7(x + 3y)² - 2x - 6y in the form of factors is :

1. (9x² + 21xy)(x + 6y)

2. 9(x + 3y)(x + 3y - 1)

3. (x + 3y)(7x + 21y - 2)

4. 7(x + 3y)(x + 3y - 3)

8(x - y) + 5(y - x) in the form of factors is :

1. 3(x + y)

2. 13(x - y)

3. 3(x - y)

4. 13(x + y)

$4x^2 + \dfrac{1}{4x^2} - 2 - 6x + \dfrac{3}{2x}$ in the form of factors is :

1. $\Big(2x + \dfrac{1}{2x}\Big)\Big(2x - \dfrac{1}{2x} - 3\Big)$

2. $\Big(2x - \dfrac{1}{2x}\Big)\Big(2x - \dfrac{1}{2x} + 3\Big)$

3. $3\Big(2x + \dfrac{1}{2x}\Big)\Big(2x + \dfrac{1}{2x} - 3\Big)$

4. $\Big(2x - \dfrac{1}{2x}\Big)\Big(2x - \dfrac{1}{2x} - 3\Big)$

3ab - 6b + 4a² - 8a in the form of factors is :

1. (a + 2)(4a + 3b)

2. (a - 2)(4a + 3b)

3. (a - 2)(4a - 3b)

4. (a + 2)(4a - 3b)