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If p and q are the roots of the equation x2 – px + q = 0, then ______. - Mathematics

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Question

If p and q are the roots of the equation x2 – px + q = 0, then ______.

Options

  • p = 1, q = –2

  • p = 1, q = 0

  • p = –2, q = 0

  • p = –2, q = 1

MCQ
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Solution

If p and q are the roots of the equation x2 – px + q = 0, then p = 1, q = –2.

Explanation:

Given that p and q be the roots of the equation x2 − px + q = 0

Then find the value of p and q.

Here, a = 1, b = –p and, c = q

p and q be the roots of the given equation

Therefore, sum of the roots

`p + q = (-b)/a`

= `(-p)/1`

= –p

q = –p – p

= –2p       ...(i)

Product of the roots

`p xx q = q/1`

As we know that `p = q/q`

= 1

Putting the value pf p = 1 in equation (i)

q = −2 × 1

= –2

Therefore, the value of p = 1; q = –2

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Chapter 4: Quadratic Equations - Exercise 4.15 [Page 83]

APPEARS IN

RD Sharma Mathematics [English] Class 10
Chapter 4 Quadratic Equations
Exercise 4.15 | Q 13 | Page 83

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