已知2x^2=50,y^3=-8,求x-y的算数平方根-搜答案-智慧作业帮

(2x+y)/(x^2-2xy+y^2)X(x-y)=(2x+y)/（x-y）²*（x-y)=(2x+y)/（x-y）x-3y=0,x=3y(2x+y)/（x-y）=（6y+y）/（3y-y

2x-3y=0(1)3x-y-1=0(2)由（2）得y=3x-1(3)把y=3x-1代入(1)得2x-9x+3=0∴x=3/7把x=3/7代入（3）得y=2/7∴x=3/7y=2/7

3x-3=2y-33x=2yx=2y/3x-y/x+y=(y/3)/(5/3)=1/5

4x-2y=0→y=2x,把所有的y都用2x替代.结果是-1/7

2x-y/x+2y是(2x-y)/(x+2y)吧(2x-y)/(x+2y)=(2x/y-1)/(x/y+2)=(2X2/3-1)/(2/3+2)=1/3÷8/3=1/8

3x=8yx/y=8/3（1）x+y/y=x/y+1=8/3+1=11/3(2)2x+3y/x-2y分子分母同时除以y得=(2x/y+3)/(x/y-2)=(16/3+3)/(8/3-2)=(25/3

(x²-y²)/(x-y)=27/3(x+y)(x-y)/(x-y)=9x+y=9①x-y=3②①+②2x=12x=6①-②2y=6y=3y/x=3/6=1/2

3x-4y/2x+y=1/26x-8y=2x+y4x=9yx/y=9/4

y=4x/5所以原式=(3x+4x/5)/(x-8x/5)=(19x/5)/(-3x/5)=-19/3

X+Y分之X-Y等于3x=-2yX+Y分之2(x-y)减X+Y分之3X+Y=(-x-3y)/(x+y)=1

2x=2-3yx>0则2x>0所以2-3y>0y

因为(x-y)/(x+y)=3,则(x＋y)/(x－y)＝1/3则5(x-y)(x+y)-(x+y)/2(x-y)＝5*3-1/(3*2)=15-1/6=89/6

（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y=（x+y)（x-y)-y^2+（x-y)^2-2y（3x^2-xy)÷2y=（x+y)（x-y)-y^2+（x-y)^2

x-2y/2x+3y=3/44(x-2y)=3(2x+3y)4x-8y=6x+9y-2x=17yx/y=-17/2

原式=(x-y)²-3(x-y)+1=3²-3×3+1x-y用3代替=1再问：3X+3Y是怎么转化成这个的3(X-Y)，什么理由再答：是-3x+3y不是3x+3y

(x-2y)/(3y-x)=2/33(x-2y)=2(3y-x)3x-6y=6y-2x5x=12y,代入原方程检验通过,故y/x=5/12

x-2y=3则：x=2y+3代入原式,原式=(4y+6+y-6)/(6y+9-y-9)=5y/5y=1

x/y=3/2则2x=3y带进去就变成6y-9y/（3y+3y）=-1/2y感觉怪怪的.一般都是转换下形式然后带进去这题怎么没一般项--或者直接将x=3y=2带进去

已知x+2+|y-3|=0

∵x+2≥0，|y-3|≥0且x+2+|y-3|=0，∴x+2=0，|y-3|=0，∴x+2=0，y-3=0，解得x=-2，y=3，当x=-2，y=3时，x2+y2+3=(-2)2+32+3=16=4

原式=x-x+x-x+……-x+(2-1+4-3+5-4+……+2008-2007-2009）y=0+(1×1004-2009)y=-1005y=1005/2