Question

If the equation x²+ax+b=0 and x²+bx+a=0(a≠b) have a common root then a+b= ?

(quadratic eqns)

Answer 1

Answer:

let alpha be the common root

alpha^2+a alpha+b=0

alpha^2+b alpha+a=0

subtracting above 2 eqns and Sol for alpha we get alpha =1

putting the value of alpha in one of the above eqns we get a+b= -1