A. Since the area of a triangle is equal to A = 0.5bh, we just plug in numbers given to us:
[tex]A = \frac{1}{2}bh= \frac{1}{2}(2x+7)(4x+6)= \frac{1}{2}(8x^2+40x+42)=4x^2+20x+21 [/tex]
So, that's your answer.
B. The answer is a 2nd-degree trinomial because it has three terms and it's highest exponent is 2.
C. Polynomials are closed under multiplication because if you multiply two polynomials, you get another polynomial (except if you multiply by the inverse which is excluded anyways).
