The lengths of two sides of a triangle are shown.



Side 1: 3x2 − 2x − 1



Side 2: 9x + 2x2 − 3



The perimeter of the triangle is 5x3 + 4x2 − x − 3.



Part A: What is the total length of the two sides, 1 and 2, of the triangle? Show your work.(4 points)



Part B: What is the length of the third side of the triangle? Show your work. (4 points)



Part C: Do the answers for Part A and Part B show that the polynomials are closed under addition and subtraction? Justify your answer. (2 points)



WILL MARK BRAINLIEST PLEASE HELP