Which table shows a proportional relationship between i and y

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5

Which one is the correct answer, and why?

Someone answer this asap for the length, in feet, of a rectangular rug is represented by the expression 5x² + 2x. the width, in feet, is represented by the expression 3x². which expression represents the perimeter, in feet, of the rug? a. 8x² + 2x b. 8x² + 4x c. 16x² + 2x d. 16x² + 4x