Verified answer

5(14+б)=700

70+5б=700

5б=700-70

5б=630

б=630:5

б=126

1259-3у=602

-3у=602-1259

-3у= -657

у=-657:(-3)

у= 219

(21-z):21=0

21-z=0

-z=-21

z=21 

1)5(14+Б)=700

70+5б=700

5б=700-70

5б=630

б=630:5

б=126

2)1259-3у=602

3у=1259-602

3у=657

у=657:3

у=219

3)(21-z):21=0

1-z:21=0

z:21=1

z=21