=3/4+2+3/4+1/8-12-5/7-4-1/8=3+6/4-12-4-5/7=2/4-5/7-12=14/28-20/28-12=-3/14-12=-12又14分之3希望能帮你忙,不懂请追问,懂了请采纳,谢谢
