Question 832862
What you're looking for is the point at which Company B charges $89 (the same as Company A).
B = 75 + .7x
Set it against the Company A value
89 = 74 + .7x
Subtract 74 from each side
15 = .7x
Multiply each side by .7
10.5 = x (or in this case, M)
A charges less than B when M >10.5