解600 ≤ (15-10)x+(40-30)(80-x) ≤ 610要步骤

600 ≤ (15-10)x+(40-30)(80-x) ≤ 610
600 ≤ 5x+10(80-x) ≤ 610
600 ≤ 5x+800-10x≤ 610
600 ≤ -5x+800 ≤ 610
600 -800≤ -5x ≤ 610-800
-200≤ -5x ≤-190
38≤ x ≤40

600 ≤ (15-10)x+(40-30)(80-x) ≤ 610
600≤5x+800-10x≤610
600≤-5x+800≤610
-200≤-5x≤-190
38≤x≤40