Question

find the value of p if -5 is a root of
${2x}^{2} + px - 15$

Answer 1

Hey !

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${2x}^{2} + px - 15 \\ \\ Putting \: value \: of \: x \\ \\ 2 × {(-5)}^{2} + p(-5) - 15 \\ \\ 2 × 25 - 5p - 15 \\ \\ 50 - 15 - 5p \\ \\ 35 - 5p \\ \\ 35 = 5p \\ \\ p = \frac{35}{5} \\ \\ p = 7$

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Answer 2

Hey mate!!

Given :

P(x) = 2x² + PX - 15

Value of x = -5

$= > 2( - 5) {}^{2} + p( - 5) - 15 = 0 \\ \\ = > 2 \times 25 - 5p - 15 = 0\\ \\ = > 50 - 5p - 15 = 0 \\ \\ = > 35 - 5p = 0\\ \\ = > 35 = 5p \\ \\ = > p = \frac{35}{5} \\ \\ \therefore{p = 7}$

Thanks for the question !!

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