1) 1/3 * (3х-6) = х-2
2/7 * (7х - 21) = 2х-6
х-2 -2х+6=9
x-2x=9-6+2
-x=-1
x=1
2) 7,2*(2y-3) = 14,4y-21,6
5,4*(3y-2)=16,2y-10,8
16,2y-10,8-14,4y+21,6=1,2
16,2y-14,4y=1,2-21,6+10,8
1,8y=-9,6
y=-9,6/1,8
y=-5,33
(c+4)(5-c)+(c-3)²=5c-c²+20-4c+c²-6c+9=-5c+29
6:12=0 (ост. 12)
3:4=0 (ост. 4)
8:10=0 (ост.10)
800080-54996397-128679=54324996