
Lauren H. answered 02/02/19
Experienced High School Chemistry Teacher
2m + 12v = 81
5m + 3v = 27
5(2m + 12v = 81) 10m + 60v = 405
2(5m + 3v = 27) -(10m + 6v = 54)
54 v = 351
v = 6.5, meaning cost of video is 6.50
You can finish by substituting 6.50 for v in one of the equations and solving for m