nnaaatt6870 nnaaatt6870 18-08-2021 Mathematics contestada Find the sum. (adding and subtracting polynomials) Find the sum. (-8x - 12) + (9x + 4)= Find the sum. (-3p^3 + 5p^2 - 2p) + (3r^2 - 3r) Find the sum. ( -3p^3 + 5p^2 - 2p) + (-p^3 - 8p^2 - 15p) Find the sum. ( 9r^2+4r-7) + (3r^2-3r)