先化简再求值(X-Y分之1 x^2-xy分之2)除以2X分之X 2其中Y=-搜答案-大师作文网

x减2y分之x减y除以x方减4xy加4y方分之x方减y方=[(x-y)/(x-2y)]×[(x-2y)²/(x+y)(x-y)]=(x-2y)/(x+y)=[(1+√2-2(1-√2)]/(

y(x+y+(x+y)(x-y)-x的平方＝xy+y^2+x^2-y^2-x^2=xy=-2*(-1/2)=1

题目有误吧(x-x)x-1分之4(x-x)+(x-2)再问：(x方-x)(x-2)方再答：

解:原式=(x-y)×(xy)分之(xy)的平方-(x-y)的平方乘以(x的平方×y的平方)分之(y的平方-x的平方)=-(xy分之4)当x=2根号3,y=2-根号3时;代入-(xy分之4),结果为5

等于-2吧

利用加法交换律(1/2)*(x+y)^5+2(x+y)^2-(4/3)*(x+y)^3-(1/2)*(x+y)^5+(1/3)*(x+y)^3=(1/2)*(x+y)^5-(1/2)*(x+y)^5+

【先化简再求值】（x-1）分之x÷【(1-x分之1）-1-x】=（x-1）分之x÷（x^2/(1-x)）=-1/xx=1时,原式无意义,x=2时,原式=-1/2,x=0时,原式无意义【选择题】下列约分

x√(1/x)+√4y-2分之√x+1/y√y³=√x+2√y-√x/2+√y=3√y当x=4,y=1/9时,原式=3√y=1

x²-4y²分之x+2y=[(x-2y)(x+2y)]分之x+2y=x-2y分之1=5-2*3.5=-2

x²-16y²分之2x-8y=(x+4y)(x-4y)分之2(x-4y)=(x+4y)分之2=-(1/2)分之2=-4

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(x+y)/[1/(x^2+y^2)]/(x^4-y^4)=(x+y)(x^2+y^2)/[(x^2-y^2)(x^2+y^2)]=(x+y)/(x^2-y^2)=1/(x-y)=1/(8-11)=-

解(x-y)(x+y)-(x-2y)²+x(3x-5y)-(x-y)(x-2y)=(x²-y²)-(x²-4xy+4y²)+(3x²-5xy

x+1/2=0,y-1=0x=-1/2,y=1原式=4x²y-(6xy-8xy+4-x²y)+1=4x²y-(-2xy+4-x²y)+1=4x²y+2

原式=(x+y-x+y)/(x+y)(x-y)÷2y/(x+y)²=2y/(x+y)(x-y)*(x+y)²/2y=(x+y)/(x-y)=(√3+√2+√3-√2)/(√3+√2

原式为：x²-3xy／x²-6xy+9y²=x(x－3y)／(x－3y)²=x／x－3y再将x=-1y=3分之2代入,有原式=x／x－3y=﹣1／（﹣1）－3×

原式=(x²-4y²-x²-4xy-4y²)×(2/y)=(-8y²-4xy)×(2/y)=-16y-8x=-4+8=4

值(x-2y)²-4(x-2y)+2(x-2y)²-3(x-2y),其中x=-1,y=2分之1(x-2y)²-4(x-2y)+2(x-2y)²-3(x-2y)=