If p, q, r are roots of the equation $(x - 3) (x^{2} - 9 x - 2018) = 0$ , then $p + q + r$ is?

12

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6

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Solution

The correct option is A $12$
$(x - 3) (x^{2} - 9 x - 2018) = 0$
$\Rightarrow$ $x^{3} - (9 + 3) x^{2} + (9 \times 3 - 2018) x + 3 \times 2018 = 0$
We know that the sum of roots of a cubic equation is equal to negative of coefficient of $x^{2}$
The coefficient of $x^{2}$ is $- 12$
$∴$ $p + q + r = 12$

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