Question

The lengths of two sides of a triangle are shown below:

Side 1: 5x2 + 2x - 3
Side 2: 8x - 3x2 + 2

The perimeter of the triangle is 2x3 - 5x2 + 4x - 8.

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

Part B: What is the length of the third side of the triangle? (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)

Answer 1

@amistre64

Answer 2

@perl

Answer 3

I am so sorry but, I don't know how to do this. sorry... :(

Answer 4

Part A. Just add side 1 and side 2, combining similar terms and being careful of signs.
Side 1: 5x2 + 2x - 3 + Side 2: 8x - 3x2 + 2 =----------------

Answer 5

2x2+10x-1

Answer 6

Yes, now subtract that sum from the perimeter and you will have Part B.

Answer 7

so wait thats part A?

Answer 8

Part B: 2x^3-7x^2+14x-16?

Answer 9

I did not get that You are subtracting 2x2+10x-1) from 2x3 - 5x2 + 4x -8 (the perimeter. I differ with you on the x term and the numeric (the 14x -16)

Answer 10

4x+16?

Answer 11

no just subtracting so 4x

Answer 12

or -6x

Answer 13

okay so its 2x^3-3x^2-6x

Answer 14

4x -10x = -6x

Answer 15

-8 -(-1) = -7

Answer 16

so 2x^3-3x^2-6x-7?

Answer 17

All together 2x3 - 7x2 -6x - 7

Answer 18

okay okay i understand i got it now. what about c?

Answer 19

Yes, demonstrated by the fact when you combine the side 1, side 2 and the result of side 3 you get the given perimeter.

Answer 20

im confused how is that part C?

Answer 21

That is part C.

Answer 22

okay

Answer 23

You could show this by adding side 1 , side 2 and the answer you got for Part B and showing that result is equal to the given Perimeter.

Answer 24

okay your a huge help do you think you can help me finish out my study guide?

Answer 25

it only has 4 more questions that im stuck on.

Answer 26

I gotta run now as my mothers therapist is here and I need to observe.