Simplify (5xy-8x^(4)y+2y^(3))+(7x^(4)y+7xy-4 y^(3))

Which of the following is not a subset of {1,2,3}?

The sum of the speeds of two trains is 720.2 mph. if the speed of the first train is 7.8 mph faster than the second train, find the speeds of each.

As voters exit the polls, you ask a representative random sample of voters if they voted for a proposition. if the true percentage of voters who vote for the proposition is 63%, what is the probability that, in your sample, exactly 5 do not voted for the proposition before 2 voted for the proposition? the probability is