x y 的平方减去6y减去6x加9-搜答案-智慧作业帮

x^2y^2-4xy+x^2+y^2+1=(xy)^2-2xy+1+x^2-2xy+y^2=(xy-1)+(x-y)^2=0xy-1=0,x-y=0,x^2=y^2=1,x=y=1或x=y=-1x+y

A=2x的平方-3xy+y的平方-x+2y；B=4x的平方-6xy+2y的平方-3x-y；则B-2A=-x-5y；又因为B-2A=a推出-x-5y=a；又因为绝对值x-2a+（y+3）的平方=0；推出

x的平方减去3x加1等于0求2x的平方减去6x加3x²-3x+1=0两边同乘以2得：2x²-6x+2=0两侧同加上1得：2x²-6x+3=1所以：2x²-6x+

3x^2+2xy+y^2-6x-6y+9=0(x+y)^2-6(x+y)+9=0(x+y-3)^2=0x+y=3

x^2+2x+y^2-6y+10=0(x+1)^2+(y-3)^2=0x=-1y=3

问题那个4y和6y里面有个应该是4x.x^2+y^2-4x+6y+13=0x^2-4x+4+y^2+6y+9=0(x-2)^2+(y+3)^2=0所以x=2,y=-3.因此x+y=-1

x^2-y^2=4xyx/y-y/x=4(x/y-y/x)^2=16(x/y)^2-2x/y*y/x+(y/x)^2=16x^2/y^2-2+y^2/x^2=16x^2/y^2+y^2/x^2=18(

x的平方加上7倍的xy减去6倍的xy的平方等于0两边乘以x/y²,得：（x/y）²+7（x/y）-6=0,即x/y=（-7±根号73）/2,

因式分解（x-2y)(x-3y）=0x=2y或x=3y,所以x:y为2或3

(x+y)²=x²+y²+2xy=49=x²+y²+24∴x²+y²=25(x-y)²=x²+y²-

6xy^2-9x^2y-y^3=-y(-6xy+9x^2+y^2)=-y(9x^2-6xy+y^2)=-y(3x-y)^2

x（x-1）-（x的平方-y）=-6x²-x-x²+y=-6-x+y=-6x-y=6二分之x的平方+y的平方减去xy=2分之(x²+y²-2xy)=2分之(x-

如果问题是：1／2（x的平方＋y的平方）－xy=2

3x^2-4x+6=93x^2-4x=3x^2-4/3x=1x^2-4/3x+6=1+6x^2-4/3x+6=7

2x^2+xy-y^2-4x+5y-6=(2x-y)(x+y)-(4x-5y)-6=(2x-y+2)(x+y-3)

y=2x^3-6x^2-18x+3求导,得y′=6x^2-12x-18令y′=0即6x^2-12x-18=0x^2-2x-3=0(x-3)(x+1)=0x=3或者x=-1由于y′=6x^2-12x-1

x²-2y²-xy+3x+2=(x²+xy-2xy-2y²)+(x-2y)+(2x+2y+2)=x(x+y)-2y(x+y)+(x-2y)+2(x+y+1)=(

-12xy*3x^2y-x^2y*(-3xy)=-36x^3y^2+3x^3y^2=33x^3y^2

题目有问题,x,y为整数x^2+xy-2y^2=7(x+2y)(x-y)=7x,y为整数x+2y=7x-y=1,3y=6,y=2,x=3,xy=6x+2y=1x-y=7,3y=-6,y=-2,x=5,