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

ConceptSolutions of Quadratic Equations by Factorization

#### 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?

#### APPEARS IN

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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