Question

Доказать тождество
a-(4a-11)+(9-2a)=20-5a

6(3b-4)-5(3b-11)+2=3b+33

Answer 1

1)
а-(4а-11)+(9-2а)=20-5а
а-4а+11+9-2а=20-5а
-5а+20=20-5а
20-5а=20-5а
2)6(3b-4)-5 (3b-11)+2=3b+33
18b-24-15b+55+2=3b+33
3b+33=3b+33