1. 2a+3a 2. 7x-15x 3.-17d+3d 4.-2,1y+7y 5. 2,5x+x 6. -a-0,8a 7. 1/3x-2x 8. 1/2a+1/5a 9. 5/6b-b
1)5а 2)-8х 3)-14d 4) 4.9 5)3.5х 6)1,8а 7)-5/3х 8)7/10а 9)-1/6b
1. 2а+3а= а(2+3)=а=5. 2. 7х-15х; х=15-7; х=8. 3. -17d+3d; d=17-3; d=14. 4. -2.1y+7y; y=2.1-7; y=-4.9.