80x - 3x*90 + 430 = 1600/280x - 270x + 430 = 800-190x + 430 = 800-190x = 370x = 370 / (-190)x = -1.94736842105
80x - 3x*90 + 430 = 1600/2
80x - 270x + 430 = 800
-190x + 430 = 800
-190x = 370
x = 370 / (-190)
x = -1.94736842105