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Please help! 1) Find the inverse of the matrix [ -9 5 6 -3 ]
2) solve the following equation
| 0 0 -1 |
| 3 x 0 | =x^2
| 2 0 3 |
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Co-factor the determinant along the first row.
(see the lesson Co-factoring the determinant of a 3x3 matrix in this site to learn how to do it).
Then the determinant is (-1)*det = (-1)*(-2x) = 2x.
So your equation is
= ,
and its roots are x=0 and/or x = 1.
Regarding your first question, do you know that only square matrices have the inverse?