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By the method of matrix inversion, solve the system. `[(1,1,1),(2,5,7),(2,1,-1)][(x_(1),y_(1)),(x_(2),y_(2)),(x_(3),y_(3))]=[(9,2),(52,15),(0,-1)]` |
Answer» Correct Answer - `x_(1)=1, x_(2)=3, x_(3)=5` or `y_(1)=-1, y_(2)=2, y_(3)=1` We have `[(1,1,1),(2,5,7),(2,1,-1)] [(x_(1),y_(1)),(x_(2),y_(2)),(x_(3),y_(3))]=[(9,2),(52,15),(0,-1)]` `implies AX=B` (1) Clearly `|A|=-4 ne 0`. Therefore, `:." adj A"=[(-12,16,-8),(2,-3,1),(2,1,3)]^(T)=[(-12,2,2),(16,-3,-5),(-8,1,3)]` `:. A^(-1)=("adj. A").(|A|)=(-1)/4 [(-12,2,2),(16,-3,-5),(-8,1,3)]` Now, `A^(-1)B=(-1)/4 [(-12,2,2),(16,-3,-5),(-8,1,3)][(9,2),(52,15),(0,-1)]` `=(-1)/4 [(-4,4),(-12,-8),(-20,-4)]=[(1,-1),(3,2),(5,1)]` From Eq. (1), we get `X=A^(-1) B` `implies [(x_(1),y_(1)),(x_(2),y_(2)),(x_(3),y_(3))]=[(1,-1),(3,2),(5,1)]` `implies x_(1)=1, x_(2)=3, x_(3)=5` or `y_(1)=-1, y_(2)=2, y_(3)=1` |
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