The total cost that a customer should incur in its dealings with company A should be,
c = 50t + 100
For company B
c = 60t + 80
Equating these two charges
c = 50t + 100 = 60t + 80
Thus, the answer is the fourth choice.
4x=20
4/4x=20/4
x=5
u want to isolate the variable to solve these equations