若xy/(x+y)=3,则(6x+4xy+6y)/(9x+4xy+9y)=______

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/28 15:32:08
若xy/(x+y)=3,则(6x+4xy+6y)/(9x+4xy+9y)=______
x){ѽR_BRXiL mJmJM} K(6IE$/!ϦH{:"#j5 fp m s% XrC#8S$\#CLF~qAb48lD<_t{> $7b։f{޲l&غg?]ٜZ**![QpL6,mda @?]d⧭K֏#ȵB.

若xy/(x+y)=3,则(6x+4xy+6y)/(9x+4xy+9y)=______
若xy/(x+y)=3,则(6x+4xy+6y)/(9x+4xy+9y)=______

若xy/(x+y)=3,则(6x+4xy+6y)/(9x+4xy+9y)=______
XY/(X+Y)=3,XY=3(X+Y)
原式=[6(X+Y)+4XY]/[9(X+Y)+4XY]
=[6(X+Y)+12(X+Y)]/[9(X+Y)+12(X+Y)]
=[18(X+Y)]/[21(X+Y)]
=18/21
=6/7

xy/(x+y)=3可得xy=3(x+y)
则原式(6x+4xy+6y)/(9x+4xy+9y)=6xy/7xy=6/7

6/7

显然xy=3(x+y)
替换所有的xy
=(6x+4*3(x+y)+6y)/(9x+4*3(x+y)+9y)
=[18(x+y)]/[21(x+y)]
=18/21
=6/7

xy/(x+y)=3 则xy=3(x+y) 代入得
(6x+4xy+6y)/(9x+4xy+9y)
=[18(x+y)]/[21(x+y)]
=18/21
=6/7