(6x-0.6)/7-(9x-0.4)/4=-(4x+0.1)/3
(60x-6)/70-(90x-4)/40=-(40x+1)/30
72000x-7200-189000x+8400=-112000x-2800
72000x-189000x+112000x=-2800+7200-8400
-5000x=-4000
x=0.8
(6x-0.6)/7-(9x-0.4)/4=-(4x+0.1)/3
(60x-6)/70-(90x-4)/40=-(40x+1)/30
72000x-7200-189000x+8400=-112000x-2800
72000x-189000x+112000x=-2800+7200-8400
-5000x=-4000
x=0.8