(x^2 + 8x^3 - 3) + (2x^2 + 9 + 5x^3) + (4x^2 - 6x - 7)

(x^2 + 8x^3 - 3) + (2x^2 + 9 + 5x^3) + (4x^2 - 6x - 7)

x^2 + 8x^3 - 3 + 2x^2 + 9 + 5x^3 + 4x^2 - 6x - 7

x^2+ 2x^2+ 4x^2 + 8x^3+ 5x^3 - 3+ 9- 7 - 6x

7x^2 + 13x^3 -1 - 6x