1)The dimensions of ST.

Question

S[7/12 -1/9]
[-1/3 1/9]

T[4 -5 2]
[8 -1 3]
answer=2x3

2)The pair of matrices that are inverses.
P[3 1] Q[4 4] R[0 -1/4]
[-4 0] [12 21] [1 3/4]

S[7/12 -1/9] T[4 -5 2] U[-9 6 4]
[-1/3 1/9] [8 -1 3] [-5 -2 3]

V[3 1]
[0 2]
[-4 5]
answer=S and R

3)Find the value of [15 4]
[-6 -2]
answer=-6

4)Evaluate:[1 4 -1]
[0 3 5]
answer=10