келеняша (0,8х+3,2):0,4-7.2=1,8
0.8х+3.2:0.4-7.2=1.8
0.8х=1.8х-3.2*0.4-7.2
0.8х=-7.76:0.8
х=-9.7
ответ:(0.8х+3.2):0.4-7.2=1.8;   х=-9.7