Question

If the quadratic equation 2x2 – kx + 9 = 0 has equal roots, then the value of k is

Answer 1

$2 {x}^{2} - kx + 9 = 0$

If the quadratic equation has equal roots, discriminant = 0

${b}^{2} - 4ac = 0$

${k}^{2} - 4 \times 2 \times 9 = 0$

${k}^{2} - 72 = 0$

${k}^{2} = 72$

$k = 6 \sqrt{3}$