the total revenue for a bluetooth speaker (in dollars) is given by R(x)=35x-0.01x^2 where x is the number of units sold. what is the average rate of change in revenue as the number of bluetooth speakers sold increased from 20 to 40 units?​

15. jiovanni is looking in to two different companies that offer study guides for math exams.test prep 101 charges a $5 flat fee and an additional $0.25 per problem.math charges a $2 flat fee and an additional $0.50 per problem.how many prablems would make the costs of the two companies be equal? varibles: equations/eniqualities{ {