Which expression is equivalent to sqrt 8x^7y^8? Assume x>0

Aline on the wall and a line on the floor are skew. always, sometimes, or never?

You deposit $5000 each year into an account earning 3% interest compounded annually. how much will you have in the account in 30 years?

An airplane travels at an unknown elevation before it descends 3 miles to an elevation of 15 miles. find the elevation of the plane before its descen.