5y+3(7y+18)=106 с проверкой
5y+21y+54=106
26y=106-54
26y=52
y=2
5y+3(7y+18)=106 5y+21y+54=106 26y=52 y=52:26 y=2 5•2+21•2+54=106
5y+3(7y+18)=106 5y×7y+3×7y+5y×18+3×18 = 35y+3×7y+5y×18+54 = 106 35y+3×7y+5y×18 = 106-54 = 52 35y+21y+90y=52 146y=52 y=52:146 y=0,35616438...