If 4 is a root of the equation x² + kx - 4 = 0; the value of k is :

1. 3

2. -3

3. 2

4. -2

The equation 2x² - 3x + k = 0 is satisfied by x = 2; the value of k is :

1. -2

2. 2

3. 4

4. 3

If $\sqrt{\dfrac{2}{3}}$ is a solution of equation 3x² + mx + 2 = 0, find the value of m.

$\dfrac{2}{3}$ and 1 are the solutions of equation mx² + nx + 6 = 0. Find the values of m and n.