作业帮1、如果1/x+1/y=2,求3x+2xy+3y/2x-3xy+2y的值
来源：学生作业帮 编辑：作业帮 分类：数学作业 时间：2024/06/09 22:48:10
1、如果1/x+1/y=2,求3x+2xy+3y/2x-3xy+2y的值
2、(1+1/2+1/3+1/4)*(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)*(1/2+1/3+1/4)
2、(1+1/2+1/3+1/4)*(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)*(1/2+1/3+1/4)
1题：1/x+1/y=2
∴(x+y)/xy=2
∴x+y=2xy
∴原式＝[3（x+y)+2xy]/[2(x+y)-3xy]
=(8xy)/(xy)=8
2题：原式＝、(1+1/2+1/3+1/4)*(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)*(1+1/2+1/3+1/4)+（1+1/2+1/3+1/4+1/5)
＝（1+1/2+1/3+1/4）*[(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)+（1+1/2+1/3+1/4+1/5)
=-(1+1/2+1/3+1/4)+(1+1/2+1/3+1/4+1/5)
=1/5
∴(x+y)/xy=2
∴x+y=2xy
∴原式＝[3（x+y)+2xy]/[2(x+y)-3xy]
=(8xy)/(xy)=8
2题：原式＝、(1+1/2+1/3+1/4)*(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)*(1+1/2+1/3+1/4)+（1+1/2+1/3+1/4+1/5)
＝（1+1/2+1/3+1/4）*[(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/5)+（1+1/2+1/3+1/4+1/5)
=-(1+1/2+1/3+1/4)+(1+1/2+1/3+1/4+1/5)
=1/5
已知：x-y=1,xy=-2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
x-y=1,xy=2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
.已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
已知:xy+x=-1,xy-y=-2,求多项式-x-[2y-2(xy+x)的平方+3x]+2[x+(xy-y)的平方]的
若1/x-1/y=3 求 2x-3xy-2y/x-2xy-y的值
已知1/x-1/y=3,求 2X+3XY-2Y/X-2XY-Y 的值//!
若1/x-1/y=3,求(2x+3xy-2y)/(x-2xy-y)的值
已知1/x+1/y=3,求x+xy+y/2x-3xy+2y的值.
已知1/x+1/y=3,求x+xy+y/2x-3xy+2y的值
已知1/x+1/y=5,求x+2xy+y/2x-3xy+2y的值
已知1/x+1/y=8,求2x-3xy+2y/x+2xy+y的值