Explain why the matrices are or are not invertible Explain i

Explain why the matrices are or are not invertible

Explain in words why the following matrices are or are not invertible, but do not find the inverse matrix.

matrix (a) - Det=y

matrix (b) - is not square matrix

matrix (c) - is Det=0

but for MATRIX (d) Det is notequal to zero and also INVERSE EXISTS.i.e. Det(d)= - 40

so I CAN CONCLUDE THAT INVERSE EXIST FOR MATRIX (d) only.