True or False
1. If a matrix has 4 rows and 5 columns then the number of elements in that matrix is 9. 2. A square matrix A= [aij] is called diagonal matrix if aij =0 for i = j. 3. Identity matrix is not a diagonal matrix. 4. If A= [aij] 2x3 and B= [bij] 3x4 then order of (AB) is 2x4 5. If all the entries in a matrix are multiplied by scalar k than whole matrix is multiplied by 3k. 6. In (AB) -1= A-1B-1 when A&B are matrices. 7. Inverse of every matrix exist.