Question

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

Options

• 1

• 2

• -2

• -1

Answer 1

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`.