Step-by-step explanation:
Given
- Side 1: 3x² - 2x - 1
- Side 2: 9x + 2x² - 3
- Perimeter: 5x³ + 4x² - x - 3
Part A
Sum of side lengths 1 and 2
- 3x² - 2x - 1 + 9x + 2x² - 3 =
- 5x² + 7x - 4
Part B
The perimeter is the sum of all three sides.
The length of the third side is
- P - (side 1 + side 2) =
- 5x³ + 4x² - x - 3 - (5x² + 7x - 4) =
- 5x³ + 4x² - x - 3 - 5x² - 7x + 4 =
- 5x³ - x² - 8x + 1
Part A - addition
Part B - subtraction