Step-by-step explanation:
first line multiplied with first column. then with second column. and then third.
then the same for the second line and then the third line.
BA11 = 5×3 + 7×3 + 3×2 = 38
BA12 = 5×1 + 7×6 + 3×-1 = 44
BA13 = 5×2 + 7×-4 + 3×-3 = -27
BA21 = -2×3 + -1×3 + 9×2 = 9
BA22 = -2×1 + -1×6 + 9×-1 = -17
BA23 = -2×2 + -1×-4 + 9×-3 = -27
BA31 = 4×3 + 3×3 + 1×2 = 23
BA32 = 4×1 + 3×6 + 1×-1 = 21
BA33 = 4×2 + 3×-4 + 1×-3 = -7
