(xy-x的平方)÷x-y xy-搜答案-搜搜考试网

∵正数x，y满足2x+y-3=0，∴3=2x+y．∴x+2yxy=13(2x+y)(1y+2x)=13(5+2xy+2yx)≥13(5+22xy•2yx)=3，当且仅当x=y=1时取等号．则x+2yx

1、原式=[2x/(x^2-1)]-[(x+1)/(x^2-1)]=[2x-(x+1)]/(x^2-1)=(x-1)/(x^2-1)=(x-1)/[(x+1)(x-1)]=1/(x+1)2、原式=[x

=-(x+2y)(x-2y)/(x+y)²×2x(x+y)/(x-2y)=-2x(x+2y)/(x+y)=-(2x²+4xy)/(x+y)

y/(x²-xy)+2/(y-x)-x/(y²-xy)=[y²+2(-xy)+x²]/(x²y-xy²)=(x-y)²/[(x-y

2x+3y=53y=5-2xy=(5-2x)/33x^2+12xy+y^2=3x^2+12x(5-2x)/3+(5-2x)^2/9x=4时=48-48+1=1

y=3x/5原式=x/(x+3x/5)+(3x/5)/[x-3x/5]-(9x^3/25)/(x^3-9x^3/25)=8/3-3/2-9/16=29/48

=(xy-x的平方）除以(x的平方-2xy+y的平方\xy)乘以(x-y\x的平方)=-x（x-y）×xy/（x-y）2×（x-y）/x2=-y再问：嗯

(1)XxX+yxy=(x+y)^2-2xy=4^2+2*12=16+28=44(2)XxXxy+Xxyxy=xy*(x+y)=4*(-12)=-48不懂可追问,有帮助请采纳,谢谢!

y的平方-xy分之(x+y)的平方÷{-（x-y）的平方分之y的平方+xy}=(x+y)²/[y(y-x)]÷[-y(y+x)/(x-y)²]=(x+y)²/[y(x-y

xy+x/x的平方+2x+1=x(y+1)/(x+1)^2不能继续约分了题目如果是xy+y/x的平方+2x+1=y(x+1)/(x+1)^2=y/(x+1)

原式=x^2/xy-y^2/xy-[(x-y)y]/[(y-x)x]=x/y-y/x+y/x=x/y.

3x²+2x²-3x-(-x+5x²)=3x²+2x²-3x+x-5x²=-2x其中x=314时,-2x=-2*314=-6285xy-8x

x的平方-2xy/xy-2y的平方＝x(x-2y)/y(x-2y)=x/y

原式(-xy/3)²*[xy(2x-y)-2x(xy-y²)]=(x²y²/9)(2x²y-xy²-2x²y+2xy²)

|3-y|+|x+y|=0，且|3-y|≥0，|x+y|≥0，所以3-y=0，x+y=0，所以y=3，x=-3．所以x+yxy=-3+3-3×3=0-9=0．答：x+yxy的值为0．

=(x+2y)(x-2y)/(x+y)×1/x(x-2y)×(x+y)(x-y)/(x+2y)(x-y)=1/x

4x的平方+3xy-x的平方-3xy+9=3x^2+9=3*(-2)^2+9=12+9=21

原式等于：1/[X(X+2Y)].再问：过程再答：原式等于：(x²-4y²)/（x²+4xy+4y²）÷(x²-2xy)=(x²-4y

(x平方+2xy+y的平方）/（x+y)=（x+y)²/(x+y)=x+y