Arectangle has sides measuring (4x + 5) units and (3x + 10) units.
part a: what is the expression that represents the area of the rectangle? show your work to receive full credit. (4 points)
part b: what are the degree and classification of the expression obtained in part a? (3 points)
part c: how does part a demonstrate the closure property for polynomials? (3 points)

Part a: area of a rectangle is length x width
                (4x + 5)(3x + 10)
                use foil to multiply the equation.
                first outer inner last
     
first, multiply 4x x 3x = 12x^2
outer, multiply 4x x 10 = 40x
inner, multiply 5 x 3x = 15x
last, 5 x 10 = 50

12x^2 + 40x + 15x + 50
12x^2 + 55x + 50

part b: the degree is 2, because 12x^2 has an exponent of 2.

part c: the product of 2 polynomials, is a polynomial.