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5x + 7y = − 2 4x + 6y = − 3 - Mathematics

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Question

5x + 7y = − 2
4x + 6y = − 3

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Solution

\[\text{ Given }: \hspace{0.167em} 5x + 7y = - 2\] 
\[ 4x + 6y = - 3\] 
Using Cramer's Rule, we get
\[D = \begin{vmatrix} 5 & 7 \\4 & 6 \end{vmatrix} = 30 - 28 = 2\] 
\[ D_1 = \begin{vmatrix} - 2 & 7\\ - 3 & 6 \end{vmatrix} = - 12 + 21 = 9\] 
\[ D_2 = \begin{vmatrix} 5 & - 2 \\4 & - 3 \end{vmatrix} = - 15 + 8 = - 7\] 
Now,
\[x = \frac{D_1}{D} = \frac{9}{2}\] 
\[y = \frac{D_2}{D} = \frac{- 7}{2}\] 
\[ \therefore x = \frac{9}{2}\text{ and }y = \frac{- 7}{2}\]

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Chapter 6: Determinants - Exercise 6.4 [Page 84]

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RD Sharma Mathematics [English] Class 12
Chapter 6 Determinants
Exercise 6.4 | Q 8 | Page 84

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