## Re: Find A and B

Originally Posted by HallsofIvy
No, it's not. "0= 0" is true for any values of A and B.

If both A and B satisfy $x^2+ Ax+ B= 0$ then $A^2+ A(A)+ B= 2A^2+ B= 0$, so that $B= -A^2$, and $B^2+ AB+ B= 0$. Since $B= -A^2$, $(-A^2)^2+ A(-A^2)+ (-A^2)= A^4- A^3- A^2= A^2(A^2- A- 1)= 0$.
Ok.