A truck can be rented from Company A for $90 a day plus $0.40 per mile. Company B charges $50 a day plus $0.80 per mile to rent the same truck. Find the number of miles in a day at which the rental costs for Company A and Company B are the same.

100 miles

Step-by-step explanation:

50 + 0.80n = 90 + 0.40n                             N = number of miles

50 - 50 + 0.80n = 90 - 50 + 0.40n

0.80n = 40 + 0.40n  

0.80n - 0.40n = 40 + 0.40n - 0.40n

0.40n = 40

0.40n/0.40 = 40/0.40

N =  100

-8/2y-8=5/y+4-7y+8/y^2-16

we move all terms to the left:

-8/2y-8-(5/y+4-7y+8/y^2-16)=0

we can not solve this equation