Find the zeros of y=x^3-4x^2-2x+1

Two planes leave an airport at the same time, one flying east, the other flying west. the eastbound plane travels 20 mph slower. they are 1600 mi apart after 2 hr. find the speed of each plane.

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?

Find the values of y: 3y^3(y^2+ 2/3y)=0