21,5(4x-1)+8(12,5-9x)=82
21.5(4х-1)+8(12.5-9х)=82
86х-21.5+100-72х=82
86х-72х=82+21.5-100
14х=3.5
х=0.25
86Х-21,5+8(12,5-9х)-82=0 86Х-21,5+100-72х-82=0 86Х+78,5-72х-82=0 14Х+78,5-82=0 14Х-3,5=0 Х=3,5:14 Х=0,25