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

问题描述:

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

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