Answer:

Step-by-step explanation:




The first one is your answer
Answer:
Step-by-step explanation:
Part A:
3x^2 -2x -1 + 9x + 2x^2-3 = 5x^2 + 7x -4
Part B
5x^3 + 4x^2 -x-3 -(5x^2 +7x-4) = 5x^3 -x^2-8x+1
Part C:
They do show polynomials are closed for addition and subtraction because both resulted in another polynomial
Here’s the answer to your question
Hope you understand it!,
THE ASWER FOR THIS IS B IM SURE OF IT :)