1. A(x) + B(x)= (3x^6 – 5x^4 +2x^2- 7) +( 8x^6 + 7x^4 – x^2 + 11)
= 11x^6 + 2x^4 +x^2 +4
2. B(x) + C(x)= 8x^6 + 7x^4 – x^2 + 11) + ( x^6 + x^4 – 8x^2 + 6
= 9x^6 + 8x^4 - 9x^2 +17
3. A(x) + B(x)- C(x)
= 11x^6 + 2x^4 +x^2 +4) - ( x^6 + x^4 – 8x^2 + 6)
= 11x^6 + 2x^4 +x^2 +4) - x^6 - x^4 + 8x^2 - 6
= 10x^6 + x^4 +9x^2 -2
4. B(x) + C(x) – A(x)
= 9x^6 + 8x^4 - 9x^2 +17 - (3x^6 – 5x^4 +2x^2- 7)
= 9x^6 + 8x^4 - 9x^2 +17 - 3x^6+ 5x^4 -2x^2+ 7
= 6x^6 +13x^4 -11x^2 +24
5. C(x) + A(x) - B(x)
= x^6 + x^4 – 8x^2 + 6 +( 3x^6 – 5x^4 +2x^2- 7) - 8x^6 - 7x^4 + x^2 - 11
= -4x^6 -11x^6 -5x^2 -12
6. A(x) + B(x) + C(x)
= [A(x) + B(x)] + C(x) = 11x^6 + 2x^4 +x^2 +4 + x^6 + x^4 – 8x^2 + 6.
= 12x^2 + 3x^4 -7x^2 +10