LiliEt 1) 1,8 - (2 3/5-(х-1,2))=3
1,8 - ( 2 3/5 - х + 1,2) =3
1,8 - 2 3/5 + х - 1,2=3
х=3-1,8+2 3/5 +1,2
х=1,2+1,2+2 3/5
х= 2 4/10+2 3/5
х=3
2)1,9-(5 3/4-(х+1))=3,15
1,9-(5 3/4-х-1)=3,15
1,9-5 3/4+х+1=3,15
х=3,15-1,9+5 3/4-1
х=1,25+5 3/4-1
х=0,25+5 3/4
х=6