Answer:
steps below
Step-by-step explanation:
3 = 2/3 m
m = 9/2
by the matrix property of associative: (A+B)+C = A+(B+C)
H = [-2 8 -1]
m x H = 9/2 x [-2 8 1] = [-9 36 -9/2]
Answer: D
19
15/4=3.75
71.25/3.75=19
28/8 = 3.5
3.5*6 = 21 km
42/6=7
7*8 = 56 miles