4mn-8m2n-2mn 1. 2mm 18x2y+x2y-45r³y 2. 9xy 3pq+14p³q-4p³q² 3. -7p³q Suv²w+uvw-3u³v²w 4. -5u3vw2 3n- m²n +2n 5. 6. 6m 30y-12x2y+9y 3x 8p²q+p²q²-4pq2 7. 2pq 8. 15p-5p³q+25p 5q 9. 49m2+14m2np³-21mnp² 10. -7m2n2p 9x2y+x²y'z-2-12xyz 3x²y²z​