The lengths of three sides of a quadrilateral are shown below:
Side 1: 1y^2+ 3y - 6
Side 2: 4y - 7 + 2y^2
SIde 3: 3y^2 - 8 + 5y
The perlmeter of the quadrilateral is 8y3 - 2y2 + 4y - 26.

Part A: What Is the total
length of sides 1, 2, and 3 of the quadrilateral?
Part B: What is the length of the fourth side of the quadrillateral?
Part C: Do the answers for Part A and Part B show that the polynomials are closed under addition
and subtraction? Justify your answer.