Question:medium
If $\begin{vmatrix} 0 & 4 & 2a \\ -2 & a & -1 \\ -1 & -2 & 5 \end{vmatrix} = -86$, then the sum of all possible values of $a$ is:
If $\begin{vmatrix} 0 & 4 & 2a \\ -2 & a & -1 \\ -1 & -2 & 5 \end{vmatrix} = -86$, then the sum of all possible values of $a$ is:
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Whenever a question asks for the "sum of all possible values" of roots from a quadratic equation, you don't need to solve for the individual roots! Just use Vieta's formula: $\text{Sum} = -\frac{b}{a}$.
Updated On: Jul 4, 2026
- 4
- 5
- $-4$
- 9
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The Correct Option is A
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