先化简再求值X-2Y分之X-Y除以X的平方减-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

(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

解【(x+2y)的平方-(x+y)(x-y)-5y方】÷(2x)=[x^2+4xy+4y^2-(x^2-y^2)-5y^2]÷(2x)=[x^2+4xy+4y^2-x^2+y^2-5y^2]÷(2x)

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

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)=-

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

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)

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=(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)=

这里^2指2次方1/2为2分之1y(x+y)-(2x+y)(x-y)-x^2=xy+y^2-(2x^2-2xy+xy-y^2)-x^2=xy+y^2-2x^2+xy+y^2-x^2=2y^2+2xy-