If -5 is a root of the quadratic equation 2x2 + px – 15 = 0 and the quadratic equation p(x2 + x)k = 0 has equal roots, find the value of k.
If the quadratic equation has two roots, then find the value of p.
The given quadratic equation has two equal roots.
therefore,
by using the discriminant method
⇒ 20p2 - 60p = 0
⇒ 20p (p - 3) = 0
⇒ p = 0 or p - 3 = 0
⇒ p = 0 or p = 3
p cannot be zero.
Hence, the value of p is 3.