Answer:
Part A: x^2 + 5x - 8
Part B: 5x^3 + 3x^2 - 6x + 5
Step-by-step explanation:
Part A:
To find the total of side 1 and 2, add the two expressions which represent each side. Combine like terms to simplify.
3x^2 − 2x − 5 + (7x - 2x^2 − 3)
3x^2 - 2x^2 -2x + 7x -5 + -3
x^2 + 5x - 8
Part B:
To solve for the third side of a triangle using its perimeter, subtract the lengths of two of its sides from its perimeter. The perimeter is 5x^3 + 4x^2 − x − 3. Subtract 3x^2 − 2x − 5 and 7x - 2x^2 − 3. The remaining expression is the third side. Combine like terms to simplify.
5x^3 + 4x^2 − x − 3 - (3x^2 − 2x − 5) - (7x - 2x^2 − 3)
5x^3 + 4x^2 - x - 3 - 3x^2 + 2x + 5 - 7x + 2x^2 + 3
5x^3 + (4x^2 -3x^2 + 2x^2) + (-x + 2x - 7x) + (-3 + 5 + 3)
5x^3 + 3x^2 - 6x + 5
