Выполню упрощение выражений пошагово:
1. $$3a+4b-2a+3-7 = (3a-2a) + 4b + (3-7) = a + 4b - 4$$
2. $$3a+2(4a-b) = 3a + 8a - 2b = 11a - 2b$$
3. $$2(4a+b)+3(a-3b) = 8a + 2b + 3a - 9b = 11a - 7b$$
4. $$4(2a-2)+4(a-b) = 8a - 8 + 4a - 4b = 12a - 4b - 8$$
5. $$7(a-2b+2)+7b = 7a - 14b + 14 + 7b = 7a - 7b + 14$$
6. $$3(a+2)-4(b+3)+2(a+1) = 3a + 6 - 4b - 12 + 2a + 2 = 5a - 4b - 4$$
7. $$2(b-4)-3(a+2b+3) = 2b - 8 - 3a - 6b - 9 = -3a - 4b - 17$$
8. $$-3(a-b)-7(2a+b) = -3a + 3b - 14a - 7b = -17a - 4b$$
9. $$2(2a-b)-4(a+3b) = 4a - 2b - 4a - 12b = -14b$$
10. $$-2(3a+2b-1)+3(a+4b-2) = -6a - 4b + 2 + 3a + 12b - 6 = -3a + 8b - 4$$
11. $$a-2(2a+b)+3(3a-2) = a - 4a - 2b + 9a - 6 = 6a - 2b - 6$$
12. $$-3(5a+b)+4(4a+b) = -15a - 3b + 16a + 4b = a + b$$
13. $$2a-4b-3(a-2b-2) = 2a - 4b - 3a + 6b + 6 = -a + 2b + 6$$
14. $$2(a+b)-3(2a+1)-2(b-3) = 2a + 2b - 6a - 3 - 2b + 6 = -4a + 3$$
15. $$3(a-2b-2)+2(a+3b+1) = 3a - 6b - 6 + 2a + 6b + 2 = 5a - 4$$
16. $$3a+2(2a+b-2)+5(b-2) = 3a + 4a + 2b - 4 + 5b - 10 = 7a + 7b - 14$$