先化简再求值已知x方减2x等于2-搜答案-智慧作业帮

先化简再求值已知2x-y=1/3,xy=2,求2x的四次方y的三次方-x的三次方y²的值这个题目是错的4x²+7x+2=44x²+7x=2-12x²-21x=-

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)]/(

由已知得x²+1=3x即（x²+1）/x=x+1/x=3x²+1/x²=(x+1/x)²-2*x*(1/x)=3²-2=7x的四次方+1/x

已知x方加y方减2x加4y等于-5x方+y方-2x+4y+5=0x方-2x+1+y方+4y+4=0(x-1)方+(y+2)方=0所以x-1=0,y+2=0所以x=1,y=-2如果不懂,请追问,祝学习愉

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已知x二次方减去5x加1等于0解得：x1=(5+根号(21))/2,x2==(5-根号(21))/2而（x^2+1/(x^2)）=(x+1/x)*(x+1/x)-2=(5*(5+根号(21))/(5+

1、x²-5x+1=0x²+1=5xx+1/x=5(x+1/x)²=25x²+1/x²+2=25x²+1/x²=232|(x

X²＋2X－1＝0两边同时除以x得x+2-1/x=0x-1/x=-2两边同时平方得x²+1/x²=6两边同时平方得x4+1/x4=34

因为x²+3x-1=0所以x^3+4x²+2x+18=x^3+3x²-x+x²+3x+18=x(x²+3x-1)+x²+3x+18=x

即x²+4x=4所以原式x³+4x²+x²-2=x(x²+4x)+x²-2=4x+x²-2=4-2=2

(x+1)(2x-1)-(x-3)²=(2x²-x+2x-1)--(x²-6x+9)=2x²+x-1-x²+6x-9=x²+7x-10=(-

x=1/(2+√3)xy=1y=(2+√3)x=1/(2+√3)x=(2-√3)/(2+√3)(2-√3)x=2-√3(x^2y-xy^2)/(x^2-y^2)=xy(x-y)/(x+y)(x-y)=

我操,你这样鬼能看懂啊?分子是啥分母是啥,那些加、除都在什么位置上啊?

因为(x-1)的二次方+(x+3)(x-3)+(x-3)(x-1)=x²-2x+1+x²-9+x²-4x+3=3x²-6x-5=3(x²-2x)-5将

x=2y=1

(x-1)^2+(x+3)(x-3)+(x-3)(x-1)=x^2-2x+1+x^2-9+x^2-4x+3=3x^2-6x-5=3(x^2-2x)-5把x^2-2x=2代人=3*2-5=1

再答：希望能帮到您！还望采纳谢谢亲

f(X)等于1+2X二次方分之X二次方f(a)=a²/(1+2a²)

=x²(x-1)/x(x-1)-(1+x)(1-x)/(x+1)=x-(1-x)=2x-1当x=2时原式=4-1=3

已知x+x分之一等于M,则2X方+2X方分之一=2(x²+1/x²)=2[(x+1/x)²-2]=2[M²-2]很高兴为您解答,skyhunter002为您答疑