14*(0.6x-6/7y)-1/8*(16.8x+6y) если=x=5/9 y=10
14*(0.6x-6/7y)-1/8*(16.8x+6y) = 8,4x - 12y - 2,1x - 3/4y = 6,3x - 12,75y если x=5/9 y=10 6,3*5/9 - 12,75*10 = 3,5 - 127,5 = -124