（6x-0.6）/7-（9x-0.4）/4=-（4x+0.1）/3（60x-6）/70-（90x-4）/40=-（40x+1）/3072000x-7200-189000x+8400=-112000x-280072000x-189000x+112000x=-2800+7200-8400-5000x=-4000x=0.8