Question:
If then, value of x is
(A) 3 (B) ± 3 (C) ± 6 (D) 6
$\left|\begin{array}{cc}2 x & 5 \\ 8 & x\end{array}\right|=\left|\begin{array}{cc}6 & -2 \\ 7 & 3\end{array}\right|$
Solution:
Option (C) ± 6
From the given,
On equating the determinants, we have
2x2 – 40 = 18 + 14
2x2 = 72
x2 = 36
Thus, x = ± 6