КС
Катя Стрелкова
0.9(х+2)=0.8(х-3)+6.4
0.9х+1.8=0.8х-2.4+6.4
0.9х-0.8х=2.2
0.1х=2.2
х=22
Вроде так
0.9x+1.8-0.8*(x-3)=6.4
0.9x+1.8-(0.8x-2.4)=6.4
0.9x+1.8-0.8x+2.4=6.4
0.1x+1.8+2.4=6.4
0.1x+4.2=6.4
0.1x=6.4-4.2
0.1x=2.2
x=2.2/0.1
x=22