(3/5-1/2-7/12)×(60×3/7-1/7×60+60×5/7)= (3/5-1/2-7/12)×60×(3/7-1/7+5/7)= (3/5-1/2-7/12)×60×1= 3/5×60-1/2×60-7/12×60= 36-30-35= -29 希望你能采纳,谢谢。