Which of the following is not a quadratic equation :

1. 2x² = 3x - 5

2. (2x - 1)(x - 1) = 2x² - 7x + 2

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

4. (x + 1)³ = x³ + 2x + 2

If 2 is a root of the quadratic equation 2x² - kx + 1 = 0, then the value of k is

1. 9

2. -9

3. $\dfrac{9}{2}$

4. $-\dfrac{9}{2}$

Which of the following quadratic equations has -1 as a root ?

1. x² + 5x + 6 = 0

2. 2x² - 3x + 1 = 0

3. 2x² + x - 3 = 0

4. 2x² - x - 3 = 0

The roots of the quadratic equation x² - 3x - 4 = 0 are

1. -4, 1

2. 4, -1

3. 4, 1

4. -4, -1