Answer?? multiplying monomials

What is the average rate of change for this function for the interval from x=2 to x=4 ?

Which is greater, 7 p 5 or 7 c 5? 7p5 7c5

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)