Question:
If $\left|\begin{array}{cc}2 x & x+3 \\ 2(x+1) & x+1\end{array}\right|=\left|\begin{array}{ll}1 & 5 \\ 3 & 3\end{array}\right|$, then write the value of $x$
Solution:
$\left|\begin{array}{cc}2 x & x+3 \\ 2(x+1) & x+1\end{array}\right|=\left|\begin{array}{cc}1 & 5 \\ 3 & 3\end{array}\right|$
$\Rightarrow(2 x)(x+1)-2(x+1)(x+3)=3-15$
$\Rightarrow(x+1)(2 x-2 x-6)=-12$
$\Rightarrow-6 x-6=-12$
$\Rightarrow-6 x=-6$
$\Rightarrow x=1$
Hence, the value of $x$ is 1 .
Click here to get exam-ready with eSaral
For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.