先化简再求值(X分之x²-Y) 其中X＝根号3-搜答案-智慧作业帮

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)]/(

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：

(x-y)分之(x²+y²)+(y-x)分之(2x-y),其中x=3+√2,y=3-√2=(x²+y²)/(x-y)-(2x-y)/(x-y)=(x²

=3x-xy+y-10xy+8x-2y=11x-11xy-y=-22+22/3-1/3=-22+7=-15

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

【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

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

原式=x²+9xy+20y²-x²+y²=9xy+21y²=9*(-8/3)*(3/7)+21*9/49=-45/7

(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)=-

3x-5y=03x=5yx/y=5/3(x-2y)/(x+3y)=(x/y-2y/y)/(x/y+3y/y)=(x/y-2)/(x/y+3)=(5/3-2)/(5/3+3)=(-1/3)/(14/3)

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

5x=-3yx=-3|5y直接带进去得答案,或者=2\3x-2|3x+2|x+y的和乘（x+y）除以x-y|x=2乘x\x-y=2（-3\5y）\（-3\5y-y）=3\4手机果然不行.

[(2x²+3xy+y²)/(x²-y²)][(5x+5y)/(2x-y)]=[(x+y)(2x+y)/(x+y)(x-y)][5(x+y)/(2x-y)]=[

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