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If a and B Are Roots of the Equation X2 + Ax + B = 0, Then a + B = - CBSE Class 10 - Mathematics

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Question

If a and b are roots of the equation x2 + ax + b = 0, then a + b =

  • 1

  • 2

  • -2

  • -1

Solution

The given quadric equation is `x^2 + ax + b = 0`, and their roots are a and b

Then find the value of  (a + b)

Let `alpha and beta` be two roots of given equation

And, a = 1, b = a and , c = b

Then, as we know that sum of the roots

`alpha + beta = (-b)/a`

`a + b = (-a)/1`

         ` = -a`

And the product of the roots

    `alpha . beta = c/a`

  `a xx b = b /1`

          ` a = 1`

Putting the value of a in above

Therefore, the value of  `a+ b = -1`.

  Is there an error in this question or solution?

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Solution If a and B Are Roots of the Equation X2 + Ax + B = 0, Then a + B = Concept: Solutions of Quadratic Equations by Factorization.
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