1: x-5/8x=15 两边同乘以8得: 8x-5x=120 3x=120 x=40
验算: 40-40×5/8=40-25=15 .
2:2/5x-3/10x=120 两边同乘以10得: 4x-3x=1200 x=1200
验算: 1200×2/5-1200×3/10=480-360=120 .
1: x-5/8x=15 两边同乘以8得: 8x-5x=120 3x=120 x=40
验算: 40-40×5/8=40-25=15 .
2:2/5x-3/10x=120 两边同乘以10得: 4x-3x=1200 x=1200
验算: 1200×2/5-1200×3/10=480-360=120 .