有几道数学题不会做哇.谁来帮帮我.明天要交的.(1)1/2x-1/x+y乘[(x+y/2x)-x-y](注意运算顺序是先乘除后加减哈.)(2)[1/(m+n)²-1/(m-n)²]÷[(1/m-n)-1/(m-n)](3)[2/3x-2/x+y(x+y/3x-x-y)]÷x-y/y照片是
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![有几道数学题不会做哇.谁来帮帮我.明天要交的.(1)1/2x-1/x+y乘[(x+y/2x)-x-y](注意运算顺序是先乘除后加减哈.)(2)[1/(m+n)²-1/(m-n)²]÷[(1/m-n)-1/(m-n)](3)[2/3x-2/x+y(x+y/3x-x-y)]÷x-y/y照片是](/uploads/image/z/604894-22-4.jpg?t=%E6%9C%89%E5%87%A0%E9%81%93%E6%95%B0%E5%AD%A6%E9%A2%98%E4%B8%8D%E4%BC%9A%E5%81%9A%E5%93%87.%E8%B0%81%E6%9D%A5%E5%B8%AE%E5%B8%AE%E6%88%91.%E6%98%8E%E5%A4%A9%E8%A6%81%E4%BA%A4%E7%9A%84.%EF%BC%881%EF%BC%891%2F2x-1%2Fx%2By%E4%B9%98%5B%28x%2By%2F2x%29-x-y%5D%EF%BC%88%E6%B3%A8%E6%84%8F%E8%BF%90%E7%AE%97%E9%A1%BA%E5%BA%8F%E6%98%AF%E5%85%88%E4%B9%98%E9%99%A4%E5%90%8E%E5%8A%A0%E5%87%8F%E5%93%88.%EF%BC%89%EF%BC%882%EF%BC%89%5B1%2F%28m%2Bn%29%26sup2%3B-1%2F%28m-n%29%26sup2%3B%5D%C3%B7%5B%281%2Fm-n%EF%BC%89-1%2F%28m-n%29%5D%EF%BC%883%EF%BC%89%5B2%2F3x-2%2Fx%2By%28x%2By%2F3x-x-y%29%5D%C3%B7x-y%2Fy%E7%85%A7%E7%89%87%E6%98%AF)
有几道数学题不会做哇.谁来帮帮我.明天要交的.(1)1/2x-1/x+y乘[(x+y/2x)-x-y](注意运算顺序是先乘除后加减哈.)(2)[1/(m+n)²-1/(m-n)²]÷[(1/m-n)-1/(m-n)](3)[2/3x-2/x+y(x+y/3x-x-y)]÷x-y/y照片是
有几道数学题不会做哇.谁来帮帮我.明天要交的.
(1)1/2x-1/x+y乘[(x+y/2x)-x-y](注意运算顺序是先乘除后加减哈.)
(2)[1/(m+n)²-1/(m-n)²]÷[(1/m-n)-1/(m-n)]
(3)[2/3x-2/x+y(x+y/3x-x-y)]÷x-y/y
照片是原题哈.
有几道数学题不会做哇.谁来帮帮我.明天要交的.(1)1/2x-1/x+y乘[(x+y/2x)-x-y](注意运算顺序是先乘除后加减哈.)(2)[1/(m+n)²-1/(m-n)²]÷[(1/m-n)-1/(m-n)](3)[2/3x-2/x+y(x+y/3x-x-y)]÷x-y/y照片是
(1)1/2x-1/(x+y)*[(x+y)/2x-x-y]
=1/2x-1/(x+y)*[(x+y)/2x-2x(x+y)/2x]
=1/2x-1/(x+y)*[(x+y)-2x(x+y)]/2x
=1/2x-1/(x+y)*(x+y)(1-2x)/2x
=1/2x-(1-2x)/2x
=[1-(1-2x)]/2x
=2x/2x
=1
(2)[1/(m+n)²-1/(m-n)²]÷[(1/(m+n)-1/(m-n)]
=[(m-n)²-(m+n)²]/[(m+n)²*(m-n)²]÷[(m-n)-(m+n)]/[(m+n)(m-n)]
=-4mn/[(m+n)²*(m-n)²]÷(-2n)/[(m+n)(m-n)]
=-4mn/[(m+n)²*(m-n)²]*[(m+n)(m-n)]/(-2n)
=2m/[(m+n)(m-n)]
=2m/(m²-n²)
(3){2/3x-2/(x+y)*[(x+y)/3x-x-y]}÷(x-y)/y
={2/3x-2/(x+y)*[(x+y)(1-3x)/3x]}÷(x-y)/y
={2/3x-2(1-3x)/3x}*y/(x-y)
=[2-2(1-3x)]/3x*y/(x-y)
=6x/3x*y/(x-y)
=2y/(x-y)
(1)=1/2x-(1/x+y)*(x+y)(1-2x)/2x=1/2x-(1-2x)/2x=1
(2)=[1/(m+n)+1/(m-n)][1/(m+n)-1/(m-n)]÷[(1/m-n)-1/(m-n)]=1/(m+n)+1/(m-n)=2m/(m+n)(m-n)
(3)=[2/3x-2/(x+y)[(x+y)(1/3x-1)]]÷(x-y)/y=[2/3x-2(1/3x-1)]÷(x-y)/y=2y/(x-y)
这什么题啊,都是直接带进括号里就出来答案了啊