Math, asked by Anonymous, 5 months ago

 x + y + z = 6, 3x - y + 3z = 10, 5x + 5y - 4z = 3.
[Find A-¹ using adjoint method.]​

Answers

Answered by MaheswariS
13

\textbf{Given:}

\mathsf{x+y+z=6}

\mathsf{3x-y+3z=10}

\mathsf{5x+5y-4z=3}

\textbf{To find:}

\textsf{Solution of the given system by inverse matrix}

\textbf{Solution:}

\textsf{The given system of equations can be wrtitten as}

\mathsf{\left(\begin{array}{ccc}1&1&1\\3&-1&3\\5&5&-4\end{array}\right)\left(\begin{array}{c}x\\y\\z\end{array}\right)=\left(\begin{array}{c}6\\10\\3\end{array}\right)}

\implies\mathsf{AX=B}

\implies\mathsf{X=A^{-1}B}

\mathsf{A=\left(\begin{array}{ccc}1&1&1\\3&-1&3\\5&5&-4\end{array}\right)}

\mathsf{|A|=1(-11)-1(-27)+1(20)}

\mathsf{|A|=-11+27+20=36}

\mathsf{Cofactor\;matrix\;of\;A}

\mathsf{=\left(\begin{array}{ccc}4-15&-(-12-5)&15+5\\-(-4-5)&-4-5&-(5-5)\\3+1&-(3-3)&-1-3\end{array}\right)}

\mathsf{=\left(\begin{array}{ccc}-11&27&20\\9&-9&0\\4&0&-4\end{array}\right)}

\mathsf{adj\,A=(cofactor\;matrix)^T}

\implies\mathsf{adj\,A=\left(\begin{array}{ccc}-11&9&4\\27&-9&0\\20&0&-4\end{array}\right)}

\mathsf{A^{-1}=\dfrac{1}{|A|}adjA}

\mathsf{A^{-1}=\dfrac{1}{36}\left(\begin{array}{ccc}-11&9&4\\27&-9&0\\20&0&-4\end{array}\right)}

\mathsf{Then,}

\mathsf{X=A^{-1}B}

\mathsf{X=\dfrac{1}{36}\left(\begin{array}{ccc}-11&9&4\\27&-9&0\\20&0&-4\end{array}\right)\left(\begin{array}{c}6\\10\\3\end{array}\right)}

\mathsf{X=\dfrac{1}{36}\left(\begin{array}{c}-66+90+12\\162-90+0\\120+0-12\end{array}\right)}

\mathsf{X=\dfrac{1}{36}\left(\begin{array}{c}36\\72\\108\end{array}\right)}

\mathsf{X=\left(\begin{array}{c}1\\2\\3\end{array}\right)}

\textbf{Answer:}

\textsf{Solution is x=1, y=2, z=3}

\textbf{Find more:}

Solve the following system of linear equations using Inverse Matrix Method. 

x + 6y – z = 10

2x + 3y + 3z = 17

3x - 3y – 2z = -9

https://brainly.in/question/16281483

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