Mr. jessup and mr allen i ready mathematics pages 77 and 78

The area of a rectangle is 54x^9y^8 square yards.if the length of the rectangle is 6x^3y^4 yards,which expression represents the width of the rectangle in yards

Which expression is not a polynomial?

Which expression do you get when you eliminate the negative exponents of 4a^2 b^216a^-3 b