If the sum of zeros of the quadratic polynomial 3x² – kx + 6 is 3 then find the value of k.

x² – 4ax + 4a ² – b ² = 0. Find the roots of this quadratic equation by the method of completing the square.

If α and β are the zeros of the polynomial 2x² + 5x + k. Find k such that (α)² + (β)² + (α) × (β) = 24.

If one root the quadratic equation 2x² + kx – 6 = 0 is 2. Find the value of "k" and also find the other root.