Groups and FieldsHardA Gallery of Groups ShareA Gallery of Groups · Hard problemHow many of the 818181 matrices (abcd)\begin{pmatrix}a&b\\c&d\end{pmatrix}(acbd) with entries a,b,c,d∈{0,1,2}a,b,c,d\in\{0,1,2\}a,b,c,d∈{0,1,2} are invertible mod 333 (i.e. lie in GL(2,Z3)GL(2,\mathbb Z_3)GL(2,Z3))?Check Show answer Walk through it step by step Practice more like this Review this concept