The lengths of two sides of a triangle are shown below:
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? (4 points)

P = side 1 +side 2 +side 3 

5x^3 +4x^2 -x -3 = 3x^2 -2x -1 + 9x +2x^2 -3 + 3rd side 

3rd side = P - (side 1 +side 2)

3rd side = 5x^3 +4x^2 -x -3 -(3x^2 -2x -1 +9x +2x^2 -3)

3rd side = 5x^3 +4x^2 -x -3 -5x^2 -7x +4

3rd side = 5x^3 -x^2 -8x +1

so the total length of the given two sides is equal 5x^2 +7x -4