( 12- х )*6.5=23.4 153+0.625у=215.5
(12-х)*6.5=23.4 12-х=23.4/6.5 12-х=3.6 х=12-3.6 х=8.4 (12-8.4))*6.5=23.4 12-8.4=3.6 3.6=3.6 153+0.625 у=215.5 0.625 у=215.5-153 0.625 у=62.5 у=62.5/0.625 у=100 153+0.625*100=215.5 153+62.5=215.5 215.5=215.5