(1-y)方-(1 y方)-搜答案-百度作业网

若X方-2XY+Y方+1XY-11=0则：x-y=0.而且xy=1所以,x=y=1,或者,x=y=-1所以,x/y=1X方+6XY+9Y方分之X方-25Y方*5X-25Y分之X+3Y=（x²

(x²+y²+1)(x²+y²+3)=8(x²+y²)²+3(x²+y²)+(x²+y²)

1.y'=sinx+xcosx2.

很高兴喂你解答!原式=4√[(x^2+xy+y^2)/(x-y)*1/2√[(x^2-xy+y^2)/(x+y)*3√(x^3+y^3)=6√[(x^2+xy+y^2)/(x-y)*√[(x^2-xy

令a=x²+y²(a+1)(a+3)=8a²+4a-5=0(a+5)(a-1)=0a=x²+y²≥0所以a=1即x²+y²=1

x^2+y^2>1?是x^2+y^2

[(x²+y²)-(x-y)²+2y(x-y)]/4y=1[x²+y²-(x²-2xy+y²)+2xy-2y²]/4y=

x+y=15两边平方x²+2xy+y²=225所以2xy=225-(x²+y²)=12xy=6所以原式=113-6=107

(x+y-1)方与根号2x-y+4互为相反数∴(x+y-1)方+根号2x-y+4=0∴x+y-1=02x-y+4=0x=-1y=2∴x²+y²=5∴x方+y方的平方根=±√5

1.x³-2x²y+xy²=x(x²-2xy+y²)=x(x-y)²2.8a²b-2b=2b(4a²-1)=2b(2a-

27·y的三次方—3y·（y+1）的二次方=3y[y²-(y+1)²]=3y(y+y+1)(y-y-1)=-3y(2y+1)169·（a—b）的二次方—196（a+b）的二次方=[

四边形F1AF2B是菱形,如图过顶点即圆半径是a利用面积法F1A=√(c²+b²)a*√(c²+b²)=bca²(c²+b²)=b

（x^2+y^2）*(x^2-1+y^2)-12=0可以设x^2+y^2=z那么有z(z-1)=12z^2-z-12=0(z-4)(z+3)=0z=4或z=-3但z是平方和一定大于0所以z=4记得采纳

x方-xy+1/4y方

(X-1/2Y)方

x²-y²-x-y=0(x+y)(x-y)-(x+y)=0(x+y)(x-y-1)=0所以x+y=0或者x-y-1=0；4x²-y²+2y-1=04x²

6已知x+y=2,x-y=1,求分式x方+2xy+y方分之x方-y方的值x方+2xy+y方分之x方-y方=(x+y)(x-y)/(x+y)²=(x-y)/(x+y)=1/27已知x分之1-y

x方(y方-1)加2x(y方-1)+(y方-1)=(y²-1)(x²+2x+1)=(y+1)(y-1)(x+1)²计算（-7x方y）（2x方y-3xy的立方+xy）=(-

4x方-y方-4x+1=(2x-1)^2-y^2=(2x-y-1)(2x+y-1)

（1）x方+2xy+y方+x+y-2=(x+y)²+(x+y)-2=(x+y+2)(x+y-1)（2）x方+xy-2y方+2x+7y-3=(x+2y)(x-y)+2x+7y-3=(x+2y-

x方-y方+2x+1等于?

x方-y方+2x+1=(x^2+2x+1)-y^2=(x+1)^2-y^2=(x+y+1)(x-y+1)