How do you factorize this expression? 8st+7su+9sv

Which statement best describes the polynomial

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

The area of a rectangle is 10 cm^2. one side of the rectangle is x cm. express the perimeter of the rectangle in terms of x and show that this rectangle cannot have a perimeter of 12 cm. the perimeter of the rectangle in terms of x is __ cm