[JEE Advanced 1986] If $x^2+ax+b=0$ and $x^2+bx+a=0$ ($a\ne b$) have a common root, then $a+b=$ ____
If $x^2+ax+b=0$ and $x^2+bx+a=0$ ($a\ne b$) have a common root, then $a+b=$ ____
1 Answer
VAVidaara Admin
✓ Vidaara Team
✓ Accepted
· 1mo ago
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Answer: $-1$.
Subtracting gives $(a-b)x+(b-a)=0\Rightarrow x=1$; substituting, $1+a+b=0\Rightarrow a+b=-1$.
JEE Advanced 1986 · Quadratic Equations and Inequations — verified solution by the Vidaara Team.
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