<span>0,3(8-3у)=3,2-0,8(у-7)
2.4-0.9у=3.2-0.8у+5.6
-0.9у+0.8у=5.6+3.2-2.4
-0.1у=6.4
у=-64</span>
1. 3х^2-2х=0
х (3х-2)=0
х=0 и 3х-2=0; 3х=2; х=2/3
2. 2х^2+3х=х^2
2х^2-х^2+3х=0
х^2+3х=0
х (х-3)=0
х=0 и х-3=0; х=3
3. 2х^2-18=0
2х^2=18
х^2=18/2
х^2=9
х=3