The inv or inverse command finds the inverse of a matrix with elements in ℤ/pℤ. (See also Section 15.1.2.)
| inv([[1,2,9]%13,[3,10,0]%13,[3,11,1]%13]) | 
or:
| inverse([[1,2,9]%13,[3,10,0]%13,[3,11,1]%13]) | 
or:
| inv([[1,2,9],[3,10,0],[3,11,1]]%13) | 
or:
| inverse([[1,2,9],[3,10,0],[3,11,1]]%13) | 
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