16th.one fast

16th.one fast (d) of th— . r„motutheequationx2 px 12 O is 4. while • px • q — Ohsequal the value of g is (d) none of these p for p. •aw •

Dear student

Given : 4 is the root of x^{2} + px + 12 = 0 \Rightarrow 4^{2} + 4 p + 12 = 0 \Rightarrow 16 + 12 + 4 p = 0 \Rightarrow 4 p = - 28 \Rightarrow p = - 7 Now the equation x^{2} + px + q = 0 ie x^{2} - 7 x + q = 0 has equal roots Also if equation has equal roots, discriminant (D) = b^{2} - 4 ac = 0 (On being compared with {ax}^{2} + bx + c = 0 where a = 1, b = - 7 and c = q) \Rightarrow {(- 7)}^{2} - 4 (1) (q) = 0 \Rightarrow 49 = 4 q \Rightarrow q = \frac{49}{4}

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