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For What Value of X the Matrix a is Singular? a = [ 1 + X 7 3 − X 8 ] - Mathematics

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Question

For what value of x the matrix A is singular? 
\[ A = \begin{bmatrix}1 + x & 7 \\ 3 - x & 8\end{bmatrix}\]

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Solution

Matrix A will be singular if  [ A ] = 0

\[\left| A \right| = \begin{vmatrix}1 + x & 7 \\ 3 - x & 8\end{vmatrix} = 0\]
\[ \Rightarrow 8 + 8x - 21 + 7x = 0\]
\[ \Rightarrow 15x - 13 = 0\]
\[ \Rightarrow 15x = 13\]
\[ \Rightarrow x = \frac{13}{15}\]

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Chapter 6: Determinants - Exercise 6.1 [Page 11]

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RD Sharma Mathematics [English] Class 12
Chapter 6 Determinants
Exercise 6.1 | Q 12.1 | Page 11

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