it says find the product, so that means multiplication
-2[7 -4 0] = [-14 8 0] solving: [-14 8 0] [-3 0 5]
[42+0+70 -24+0+40 0+0+0]
[-14 8 0] * [-3 0 5] = [112 0 -30] = [112 16 0]
[112 16 0]*[6 2 1]
[112 0 -30]* [6 2 1] = [1008 114 0] [672+224+112 96+32+16 +0]
=[1008 114 0].
