(y^2-6x)y 2y=0-搜答案-智慧作业帮

x^2+y^2-6x-8y+25=0x^2-6x+9+y^2-8y+16=0(x-3)^2+(y-4)^2=0∴x=3且y=4y/x-x/y=4/3-3/4=7/12

由已知可得（X-3)(X-3)+(Y+2)(y+2）=0,即可得X=3.Y=-2,待到问题中即可得到答案为1

x^2+y^2-6x-8y+25=0[x-3]^2+[y-4]^2=0x-3=0===>x=3y-4=0===>y=4y/x-x/y=4/3-3/4=7/12

2y错了即(x²-4x+4)+(y²+6y+9)=0(x-2)²+(y+3)²=0所以x-2=0,y+3=0x=2,y=-3

7.x*x+2*x+y*y-6y+10=(x+1)*(x+1)+(y-3)*(y-3)=0x+1=0且y-3＝0所以x*y＝-38.再加个4*x就好了11.原式＝（x-2）*（x-2）+（y+3）*（

x²+y²+13-4x+6y=0(x²-4x+4)+(y²+6y+9)=0(x-2)²+(y+3)²=0平方项恒非负,两非负项之和=0,两非

x2y−x−y2y−x＝x2−y2y−x＝(x−y)(x+y)y−x＝−(x+y)＝−x−y．故选A．

0.5--2直线方程y=k(x-1)过（1,0）,这点与三直线围成的范围有交点,K取值为0.5到20.5≤k≤2.

x+y+z-6=02x+3y-z-12=02x-y-z=0组成方程组再解x=2y=3z=1

x=-3y=4式子等于-49/12

c∵x+y≠0∴x≠-y∵3x-6y/x+y=0∴3x-6y=0∴x=2y∴x=2y且x≠-y

x^2+2x+y^2-6y+10=0（x+1)²+（y-3)²=0∴x=-1,y=3(x+y)²=（-1+3）²=4

x^2+y^2-6x-2y+10=0x^2-6x+9+y^2-2y+1=0(x-3)^2+(y-1)^2=0x=3,y=1(x+y)/(x-y)=4/2=2

x平方+8x+16+y平方+6x+9=0(x+4)平方+(y+3)平方=0∴x+4=0y+3=0∴x=-4,y=-3原式=(x+2y)(x-2y)/(x+2y)平方-x/(x+2y)=(x-2y)/(

x^2+y^2-6x+8y+25=0x²-6x+9+y²+8y+16=0(x-3)²+(y+4)²=0x-3=0x=3y+4=0y=-4y^x=-4³

由已知，得5x=z+x，即z=4x，①3x=y+z，②由①②，得y=-x，③把①③代入x−2y2y+z，得x−2y2y+z=x+2x−2x+4x=32．故选B．

x²-2x+y²+6y+10=0x²-2x+1+y²+6y+9=0(x-1)²+(y+3)²=0x-1=0y+3=0∴x=1y=-3∴x+y

x^2-2x+y^2+6y+10=0(x-1)^2+(y+3)^2=0x=1y=-3(x-y)/(x+y)=4/(-2)=-2

4x^2+y-4x-6y+10=0(2x-1)^2+(y-3)^2=0x=1/2y=3y/x-x/y=6-1/6=35/6