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

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

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

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

-3 + 8r^3 - 9r^4 + 5r^2