Aspire Faculty ID #13734 · Topic: JAMIA MILLIA ISLAMIA MCA 2022 · Just now
JAMIA MILLIA ISLAMIA MCA 2022

If $ \begin{vmatrix} x & 3 & 6 \\ 3 & 6 & x \\ 6 & x & 3 \end{vmatrix} = \begin{vmatrix} 2 & x & 7 \\ x & 7 & 2 \\ 7 & 2 & x \end{vmatrix} = \begin{vmatrix} 4 & 5 & x \\ 5 & x & 4 \\ x & 4 & 5 \end{vmatrix} = 0 $, then $x$ is equal to:

Solution

Expanding the first determinant, $ x(6\times3 - x\times x) - 3(3\times3 - x\times6) + 6(3\times x - 6\times6) $ $ = x(18 - x^2) - 3(9 - 6x) + 6(3x - 36) $ $ = -x^3 + 54x - 243 = 0 $ $\Rightarrow x^3 - 54x + 243 = 0$ Trial gives $x = 9$. $\boxed{x = 9}$ → (D) None of these.

Previous 10 Questions — JAMIA MILLIA ISLAMIA MCA 2022

Nearest first

Next 10 Questions — JAMIA MILLIA ISLAMIA MCA 2022

Ascending by ID
Ask Your Question or Put Your Review.

loading...