How do you simplify 7b-3b^5

The cost of using a service is $0.25 per min. what equation correctly represents the total cost c, in dollars, for d days of use?

For the chance to be team captain, the numbers 1-30 are put in a hat and you get two chances to pick a number, without replacement. which formula correctly shows how to find the probability that you choose the number 1 and then 2?

Solve for x: 5/3 x = 20/21 it's fraction. remember to simplify your fraction