PLEASE HELP ILL MARK YOU BRAINLIEST 30 POINTS 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. Part B: What is the length of the third side of the triangle? Show your work. Part C: Do the answers for Part A and Part B show that the polynomials are closed under addition and subtraction? Justify your 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

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: No because they both formed another polynomial

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step-by-step explanation:

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225