Find the greatest value of k ∈ N for which the equation x² - 4x + k = 0 has distinct real roots.

1. -4

2. 3

3. 1

4. 4

If the quadratic equation kx² + kx + 1 = 0 has real and equal roots, the value of k is :

1. 0

2. 4

3. 0 and 4

4. 0 or 4

If x² - 7x = 0, the value of x is :

1. 7

2. 0

3. 0 and 7

4. 0 or 7

If x = 1 is a root of the equation $\sqrt{x} + kx - 2$ = 0; the value of k is :

1. 1

2. -1

3. 2

4. -2