<span>file:///Users/antonov/Pictures/Медиатека%20iPhoto.photolibrary/Masters/2015/03/22/20150322-210416/IMG_0577.JPG</span>
1) 8-7х=0
-7х=-8
х= -8/-7
х=1.14
2) 0.2х-1=3-0.8х
х=4
3) (8х+5)-(3х+10)=25
8х+5-3х-10=25
5х=30
х=6
(5c-4)^2= 25c^2-40c+16
Ответ:
25c^2-40c+16