add (9r^3+5r^2+11r)+(-2r^3+9r-8r^2)
To simplify the expression (9r^3 + 5r^2 + 11r) + (-2r^3 + 9r - 8r^2), we can group like terms together:
(9r^3 - 2r^3) + (5r^2 - 8r^2) + (11r + 9r)
Combining the like terms, we have:
7r^3 - 3r^2 + 20r
(9r^3 - 2r^3) + (5r^2 - 8r^2) + (11r + 9r)
Combining the like terms, we have:
7r^3 - 3r^2 + 20r