方程组x²-2xy-3y²=0,x² 6y=-2的解

由方程1得：x=2y-3代入方程2得：(2y-3)^2+y(2y-3)+4y^2-19=0整理得：10y^2-15y-10=05(2y^2-3y-2)=05(2y+1)(y-2)=0解得：y=-1/2

x^2-2xy-3y^2=0（x-y）^2-4y^2=0（x-y）^2=(2y)^2x-y=±2yx-y=2y或x-y=-2yx1=3yx2=-y将x1,x2分别代入②,得：（3y）^2-y*3y+y

xy/(2x+y)-xy/(2x-y)=3xy/(2x-y)+xy/(2x+y)=4；一、两公式对加得2xy/(2x+y)=7xy=(2x+y)*7/2二、把xy代入原公式求解就行了：(2x+y)*7

X²-XY+2X=O提公因数X即X（X-Y+2）=0则X=0或X-Y+2=0假如X=0那么代入X²-2XY+Y+8=0解得Y=﹣8即X=0Y=﹣8假如X≠0则X-Y+2=0即X=Y

解1式：(x+4y)(x-y)=0x=-4y时,解2式得：x=-10/3,y=5/6;x=10/3,y=-5/6x=y时,解2式得：x=5,y=5;x=-5,y=-5

x²-2xy+y²=12x²-5xy-3y²=0即(x-y)²=1(2x+y)(x-3y)=02x+y=0或x-3y=0如果2x+y=0,则y=-2x

x²-3xy+2y²=0(x-2y)(x-y)=0x=2y或x=y当x=2y时,x²+y²=104y²+y²=10,y=正负根号2；x=正负

/>2x²-3xy-2y²=0…………………………(1)x²+y²=45………………………………(2)由(1)得：(2x+y)(x-2y)=0有：2x+y=0、

x+y=-3x=-3-y带入xy=2(-3-y)y=2-y^2-3y-2=0y^2+3y+2=0(y+1)(y+2)=0y1=-1y2=-2x1=-2x2=-1

x²-xy-2y²=0(x+y)(x-2y)=0x+y=2所以x-2y=0相减3y=2所以y=2/3x=2y=4/3

x2y+xy2=xy*(x+y)因为x+y=-(7+xy)又x+y=（9+2xy)\3所以（9+2xy)\3=-(7+xy)3+2xy\3=-7-xy5xy\3=-10解得xy=-6所以x+y=-(7

由(x+y)/xy=5/6(y+z)/yz=-2/3得1/x+1/y=5/6①1/y+1/z=-2/3②1/x-1/z=3/21/z=1/x-3/2③z=2x/(2-3x)代入2(x+3)+xz=0化

x=2,y=0.5

x2+y2+2xy=9(x+y)²=9x+y=3或-3(x-y)2-3x+3y+2=0(x-y)²-3(x-y)+2=0(x-y-1)(x-y-2)=0x-y=1或2所以组成4个方

即(x+y)²=9(x-y-3)(x-y-1)=0所以x+y=3,x-y=1x+y=3,x-y=3x+y=-3,x-y=1x+y=-3,x-y=3所以x=2,y=1x=3,y=0x=-1,y

第一个,由①x+3y=7得,(x+3y)(x-3y)=x²-9y²=7(x-3y)而由2知x²-9y²=-35所以(x-3y)=-5联立①x+3y=7得x=1,

由(x-2)(y+3)=xy(x-5)(y+2)=xy得3x-2y-6=02x-5y-10=0上面方程化为6x-4y-12=06x-15y-30=0两式相减得11y=-18,y=-18/11,代入任意

x1=-1/12*(1261+234*29^(1/2))^(1/3)-13/12/(1261+234*29^(1/2))^(1/3)+5/12x2=1/24*(1261+234*29^(1/2))^(

x^2-3xy+2y^2=0(x-2y)(x-y)=0得x=2y或x=y分别代入x^2+y^2=10可得最终解为x=y=根号5或x=2根号2,y=根号2