(20-x)*120-80x=2202400-120x-80x=220120x+80x=2400-220200x=2180x=2180/200x=10.9(16-x)*1.2-0.4x=1.619.2-1.2x-0.4x=1.61.2x+0.4x=19.2-1.61.6x=17.6x=17.6/1.6x=115x-10=(x+4)*25x-10=2x+85x-2x=10+83x=18x=18/3x...