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If the Matrix [ 5 X 2 − 10 1 ] is Singular, Find the Value of X. - Mathematics

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Question

If the matrix \[\begin{bmatrix}5x & 2 \\ - 10 & 1\end{bmatrix}\]  is singular, find the value of x.

Solution

A  matrix is said to be singular if its determinant is zero. Since the given matrix is singular, we get 
\[A = \begin{bmatrix} 5x & 2 \\- 10 & 1 \end{bmatrix} \] 
\[ \Rightarrow \left| A \right| = \begin{vmatrix} 5x & 2 \\- 10 & 1 \end{vmatrix} = 0\] 
\[ \Rightarrow 5x + 20 = 0 \left[\text{ Expanding }\right]\] 
\[ \Rightarrow x = - \frac{20}{5} = - 4\] 

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Chapter 6: Determinants - Exercise 6.6 [Page 91]

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RD Sharma Mathematics [English] Class 12
Chapter 6 Determinants
Exercise 6.6 | Q 28 | Page 91

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