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If the roots of the quadratic equation px(x − 2) + 6 = 0 are equal, find the value of p |
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Answer» Given quadratic equation is px (x – 2) + 6 = 0 ⇒ px2 − 2px + 6 = 0 … (1) By comparing equation (1)with ax2 + bx + c = 0, we get a = p, b = −2p and c = 6. Since given that the given quadratic equation has equal roots. ∴ D = b2– 4ac = 0 (∵ for equal roots D = 0) ⇒(−2p)2 − 4 × p × 6 = 0 ⇒ 4p2 − 24p = 0 ⇒ 4p (p – 6) = 0 ⇒ p = 0 or p – 6 = 0 ⇒ p = 0 or p = 6 but p ≠ 0 (∵ If p = 0 then given equation is not quadratic equation) Hence the value of p is 6, for which the given quadratic equation have equal roots. |
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