If | * 20 c 2x &5 8&x | = | * 20 c 6& - 2 7&3 | , then the value of x is

2 x 2 - 40 = 18 + 14 2 x 2 = 32 + 40 = 2 = 36 x = 6

Determinants — Class 12 Maths Solution

exemplar objective MCQ NCERT,Exemp,Q.24, Page.80

Question

If $\left| {\begin{array}{cccccccccccccccccccc}{2x}&5\\8&x\end{array}} \right| = \left| {\begin{array}{cccccccccccccccccccc}6&{ - 2}\\7&3\end{array}} \right|$, then the value of $x$ is

(a) 3
(b) $\pm 3$
(c) $\pm 6$ ✓ Correct
(d) 6

Step-by-step Solution

$\Rightarrow$ $2{x^2} - 40 = 18 + 14$

$\Rightarrow$ $2{x^2} = 32 + 40$

$\Rightarrow$ ${x^2} = \frac{{72}}{2} = 36$

$\therefore x = \pm 6$

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NCERT & Exemplar solution for CBSE Class 12 Mathematics, Determinants. Curated by Sachin Sharma. Free for all students.