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共回答了17个问题采纳率:76.5% 举报
原式=(-2/3)+(1/4)-(1/6)-(1/2)
=(-8/12)+(3/12)-(2/12)-(6/12)
=(-8+3-2-6)/12
= -13/12
原式=-8-(7/2)+2-(1/2)+12
=6-4
=2
原式=-3.75+2.75
=-1
原式=(-2/3)+1.75-(1/3)-1.75
=-1
原式=(-3又2/3)+2.75+(1又2/3)+1.75
=-2+4.5
=2.5
8.原式=【31/2-(5/4÷7/5+7/2)】÷(-9/8)
=【31/2-(5/4×5/7+7/2)】×(-8/9)
=【31/2-(25/28+7/2)】×(-8/9)
=(31/2-25/28-7/2)×(-8/9)
=(24/2-25/28)×(-8/9)
=(336/28-25/28)×(-8/9)
=311/28×(-8/9)
=-622/63
1年前
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