A=⎡⎢⎣12−35021−11⎤⎥⎦,B=⎡⎢⎣3−12425203⎤⎥⎦,C=⎡⎢⎣4120321−23⎤⎥⎦ compute (A+B) and (B-C). Also verify that A+(B-C)=(A+B)-C.