If α and β are the roots of the equation x^2 + px + q = 0

If α and β are the roots of the equation x2 + px + q = 0, then what is α2 + β2 equal to?

  1. p2 – 2q
  2. q2 – 2p
  3. p2 + 2q
  4. q2 – q

Answer

Sum of roots = α + β = -p

Product of roots = αβ = q

α2 + β2 = (α + β)2 - 2αβ

= (-p)2 - 2q

= p2 - 2q

The correct option is A.