谁会数学分式
初二数学分式题
[(2x-6)/(x-2)]/[5/(x-2)-(x+2)] ==>[(2x-6)/(x-2)]/[5-(x+2)(x-2)/(x-2)] ==>(2x-6)/[5-(x+2)(x-2)] ==>[-2(3-x)]/[(3-x)(3+x)] ==>-2/(3+x)
={(2x-6)/(x-2)}÷ {[5-(x-2)(x+2)]/(x-2)} =(2x-6)/{5-(x-2)(x+2)}化简一下 =(2x-6)/(9-x^2) ={2(x-3)}/{-(3+x)(x-3)}约掉一个x-3 =?2/(x+3)
原式=2(X-3)/(X-2)÷[5/(x-2)-(X^2-4)/(X-2) =2(X-3)/(X-2)×[(X-2)/(9-X^2)] =2(X-3)/(X-2)×[(X-2)/(3+X)(3-X)] =-2/(3+X)
答:解: 设规定日期为x天,工作量为单位1,则第一组的工作效率为 1/x,第二组的工作效率为1/(x+3),合作两天完成的工作量为 2*[(1/x)+1/(x+3)...详情>>
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