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If $\alpha$ is a root of the quadratic equation $ax^2+bx+c=0$ with $a\neq 0$, then which statement must be true?
A$a\alpha+b\alpha+c=0$
B$a\alpha^2+b\alpha+c=0$
C$\alpha^2+\alpha+1=0$
D$a+b+c=0$
Answer & Solution
Correct answer: B. $a\alpha^2+b\alpha+c=0$
By definition, a real number $\alpha$ is a root of $ax^2+bx+c=0$ if substituting $x=\alpha$ makes the equation true. Therefore, $a\alpha^2+b\alpha+c=0$.
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