Докажите тосдество
1) a-(4a-11)+(9-2a)=20-5a
2) 6(3b-4)-5(3b-11)+2=3b+33

1)а-4а+11+9-2а=-5а+20=20-5а

20-5a=20-5a

2)18b-24-15b+55+2=3b+33

3b+33=3b+33

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

a-4a+11 + 9-2a =20-5a

a-4a-2a+5a=20-11-9

-7a=0

a=0÷-7

a=0

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

18b-24-15b+55+2=3b+33

18b-15b-3b=33+24-55-2

0b=0