Let's write equations for both internet services...
#months=x
B=42.95x+60...Brian's monthly service plus
installation fee
M=57.95x........Michael's monthly service
Problems asks how many months will it take for them
to pay the same amount, so we can equate the two
expressions.
B=M
42.95x+60=57.95x....expressions for Brian, Michael
60x=15x........combine like terms
15x=60
∴ x= 4...........divide both sides by 15
So it will take 4 months before each will have paid
the same. Let's check our answer be substituting
x=4 into the expresessions for Brian and Michael...
B=42.95(4)+60=171.80+60=$231.80
M=57.95(4)=.....................=$231.80
Both costs are the same after 4months, our solution
is correct. Always check your work!