Answer:
we know that, 1miles/hour = 0.45m/s
or, 1meters/second = 1/0.45
1m/s = 2.22222222222
Step-by-step explanation:
Then,
72.0 meters/second = 72.0*2.22222222222
=160 miles per hour.
817.52 should be correct
6x-21
1) draw diagram (in image)
BD=2x-21+4x
combine Like terms