Question
Without expanding, evaluate the following determinants.

(ii) $\left|\begin{array}{ccc}2 & 3 & 4 \\ 5 & 6 & 8 \\ 6 x & 9 x & 12 x\end{array}\right|$

Answer

Let $\mathrm{D}=\left|\begin{array}{ccc}2 & 3 & 4 \\ 5 & 6 & 8 \\ 6 x & 9 x & 12 x\end{array}\right|$
Taking ( $3 x$ ) common from $\mathrm{R}_3$, we get
$
\begin{aligned}
& \mathrm{D}=3 x\left|\begin{array}{lll}
2 & 3 & 4 \\
5 & 6 & 8 \\
2 & 3 & 4
\end{array}\right| \\
& \text { MaharashtraBoardSolutions.in } \\
&=(3 x)(0) \quad \ldots\left[\because \mathrm{R}_1 \text { and } \mathrm{R}_3 \text { are identical }\right] \\
&=0
\end{aligned}
$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free