2016 · Q20
If p and q are the roots of x²+px+q=0, then which one of the following is correct ?
Elementary MathematicsAlgebra
- Ap = 0 or 1
- Bp = 1 only
- Cp = -2 or 0
- Dp = -2 only
Explanation
From p+q = −p we get q = −2p, and from pq = q we get q(p−1) = 0. If q = 0 then p = 0; if p = 1 then q = −2 (indeed x²+x−2 = 0 has roots 1 and −2). So p = 0 or p = 1 (option A).