ANSWER ASAP IM BEING TIMED IF I GET AN A ON THIS I WILL DO ANOTHER POINT FREE DROP, PLEASE SHOW YOUR WORK
The lengths of three sides of a quadrilateral are shown below:

Side 1: 1y2 + 3y − 6

Side 2: 4y − 7 + 2y2

Side 3: 3y2 − 8 + 5y

The perimeter of the quadrilateral is 8y3 − 2y2 + 4y − 26.

Part A: What is the total length of sides 1, 2, and 3 of the quadrilateral? (4 points)

Part B: What is the length of the fourth side of the quadrilateral? (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)