tolong di jawab yaa jangan lupa bikin caranya,, tentang matriks

Diketahui :
P = | 2 1 | , Q = | 5 6 | , R = |-2 -3|
.......| 0 3|...........|-2 -1 |..........| 4 1|
Ditanyai :
PQ - 2R^2 = ... ?
Jawab :
PQ - 2R^2
= | 2 1 | | 5 6| _ 2|-2 -3| |-2 -3|
...| 0 3| |-2 -1|.......| 4 1| | 4 1|
= | 8 11| _ 2|-8 3|
...|-6 -3|.......|-4 -11|
= | 8 11| _ |-16 6 |
...|-6 -3|....|-8 -22|
= | 24 5 |
...| 2 19|
Jawabannya C.