A. Since the area of a triangle is equal to A = 0.5bh, we just plug in numbers given to us:

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).
They are both correct! Michael's equation is just a distributed version of Laurie's equation. Laurie's equation is solved like this: First distribute to get
2x + 1.2 + 0.8 + 0.7, then add the numbers together to get 2x + 2.7.
Michael's equation also starts with distributing to get 2x + 1.2 + 0.8 + 0.7 and adding the numbers together to get the same answer: 2x + 2.7. Hope this helps!
I get x/13 = 106/9............so 9x = 1378 therefore x = 153.1