2х:18=9
2х=9×18
х=162:2
х=81
7-(4х+2)=-3х+4
7-4х-2=-3+4
-4х+3х=4-7+2
-х=-1
х=1
Ответ: 1.
1) 10/21 - 25/28 = 40/84 - 75/84 = - 35/84
2) - 11/14 + 24/35 = - 110/140 + 96/140 = - 14/140 = - 1/10
3) - 35/84 : ( - 1/10 ) = 175/42 = 4 7/42 = 4 1/6
ОТВЕТ 4 1/6
5.1y=4.5*3.4
y=(4.5*3.4)/5.1
y=3