What is the simplified answer?

What are “like terms”? why can we only add like terms?

Is the power produced directly proportional to the wind speed, give reasons for your answer?

Atruck can be rented from company a $50 a day plus $0.60 per mile. company b charges $20 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