If x 2 + x x + 1 x - 2 2 x 2 + 3 x - 1 3 x 3 x - 3 x 2 + 2 x + 3 2 x - 1 2 x - 1 = a x - 12 , then a is equal to:

Put x = 1 on both the sides 2 2 - 1 4 3 0 6 1 1 = a - 12 ⇒ 2 3 - 0 - 2 4 - 0 - 1 4 - 18 = a - 12 ⇒ 6 - 8 + 14 = a - 12 ⇒ 12 = a - 12 ⇒ 24 = a .

Mathematics - Determinant Question with Solution | TestHub

MathematicsDeterminantProperties of det.Easy2 minPYQ_2015

MathematicsEasysingle choice

If $|\begin{matrix} x^{2} + x & x + 1 & x - 2 \\ 2 x^{2} + 3 x - 1 & 3 x & 3 x - 3 \\ x^{2} + 2 x + 3 & 2 x - 1 & 2 x - 1 \end{matrix}| = a x - 12$ , then $a$ is equal to:

Options:

Answer:

Solution:

Put $x = 1$ on both the sides

$|\begin{matrix} 2 & 2 & - 1 \\ 4 & 3 & 0 \\ 6 & 1 & 1 \end{matrix}| = a - 12$

$\Rightarrow 2 (3 - 0) - 2 (4 - 0) - 1 (4 - 18) = a - 12$

$\Rightarrow 6 - 8 + 14 = a - 12$

$\Rightarrow 12 = a - 12$

$\Rightarrow 24 = a .$

Stream:JEESubject:MathematicsTopic:DeterminantSubtopic:Properties of det.

⏱ 2mℹ️ Source: PYQ_2015

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