Saved Bookmarks
| 1. |
Find the roots of the quadratic equation 3x2 − 7x − 6 = 0.ORFind the values of k for which the quadratic equation 3x2 + kx + 3 = 0 has real and equal roots. |
|
Answer» 3x2 − 7x − 6 = 0 ⇒ 3x2 − 9x + 2x − 6 = 0 ⇒ 3x(x − 3) + 2(x − 3) = 0 ⇒ (x − 3)(3x + 2) = 0 ∵ x = 3, \(-\frac{2}{3}\) OR Since the roots are real and equal, ∴ D = b2 − 4ac = 0 ⇒ k2 – 4×3×3 = 0 (∵ a = 3, b = k, c = 3) ⇒ k2 = 36 ⇒ k = 6 or −6 |
|