Question

If -5 is a root of a quadratic equation = 2x^2 + px - 15=0 and the quadratic equation p(x^2+x)+k=0 has equal roots find the value of "k".

No google answer..​

Answer 1

Answer:

$⇢k = \frac{7}{4}$

Step-by-step explanation:

$given \: eqn. = \\ ⇢2 {x}^{2} + px - 15 = 0 \\ ⇢putting \: x = - 5 \: in \: eqn. \\⇢ 2 \times ( { - 5}^{2} ) + p \times - 5 - 15 = 0 \\ ⇢50 - 5p - 15 \\ ⇢ - 5p + 35 = 0 \\⇢ p = \frac{35}{5} \\ ⇢p = 7$

${2}^{nd} eqn. = \\⇢ p( {x}^{2} + x) + k = 0 \\ ⇢7( {x}^{2} + x) + k = 0 \\ ⇢{7x}^{2} + 7x + k = 0 \\ ⇢on \: comparing \: with \: d = {b}^{2} - 4ac \\⇢ d = 49 - 4 \times 7 \times k \\ ⇢49 - 28 \times k \\ ⇢k = \frac{49}{28} \\⇢ k = \frac{7}{4}$

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⇢original answer☑

Hope it helps you✓

Answer 2

The above answer is right