PLEASE HURRY my question is in the picture

Which is the completely factored from of xy^3-x^3y

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

Mr. jones determined that the equation y = 98 - 16/5 x could be used to predict his students' unit test scores, based on the number of days, x, a student was absent during the unit. what was the meaning of the y-intercept of the function? (by the way the 16/5 is a )