# 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)

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1. sum of 2 given sides = 3x^2 − 2x − 1 + 9x + 2x^2 − 3
= 5x^2 + 7x - 4

third side = perimeter - (sum of 2 given sides)
= 5x^3 + 4x^2 − x − 3 - (5x^2 + 7x - 4)
= 5x^3 - x^2 - 8x + 1

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2. i need help with c. i alr have the other parts.

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3. polynomials are closed under addition and subtraction, if the
results after addition and/or subtraction yields a polynomial.
Since this is what happened, it is closed

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4. jesus christ

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