已知y=x平方-9分之x² 6x 9 x²-3x分之x 3-x 3

(4x²-4x+1)+(y²-6y+9)=0(2x-1)²+(y-3)²=0所以2x-1=y-3=0x=1/2,y=3后面的看不懂

x平方+y平方+8x+6y+25=0(x+4)²+(y+3)²=0∴x=-4;y=-3∴(x²-4y²)/(x²+4xy+4y²)-x/(x

3x^2+xy-2y^2=(3x-2y)(x+y)=0x=-2y/3,或x=-y但由于你要求的式子中分母里有X平方-Y平方x=-y舍去其他就代入吧

x/y=2平方x²/y²=4原式分子分母同除以y²所以原式=(x²/y²-x/y+3)/(x²/y²+x/y+6)=(4-2+3)

(x-y)/(x+y)=(x-y)(x+y)/[(x+y)^2]=(x^2-y^2)/[x^2+y^2+2xy]=2xy/[x^2+y^2+x^2-y^2]=2xy/(2x^2)=y/xx^2-y^2

x=1/xx²=1X-3分之X的平方-6X+9再除以X的平方+6X+9分之X+3的值[(x²-6x+9)/(x-3)]/[(x+3)/(x²+6x+9)]=[(x

x^2+y^2-4x-6y+13=0(x^2-4x+4)+(x^2-6y+9)=0(x-2)^2+(y-3)^2=0所以(x-2)^2=0,(y-3)^2=0x-2=0,y-3=0x=2,y=3xy/

4x^2+9y^2-x+6y+17/16=0(4x^2-x+1/16)+(9y^2+6y+1)=0(2x-1/4)^2+(3y+1)^2=0那么2x-1/4=0,3y+1=0x=1/8,y=-1/3x

已知5x-4y=0,切xy≠0,x/y=4/5;求(x平方-y平方)分之(x平方+y平方)-(x-y)分之(x+y)的值=(x²+y²)/(x²-y²)-(x+

∵x/y=2/3∴设x=2t,y=3t∴(x²+3xy)/(x²+xy-6y²)=(4t²+3×2t×3t)/(4t²+2t×3t-6×9t²

y=2x/3则xy=2x2/3y2=4x2/9所以原式=(2x2/3)/(x2+4x2/9)-(4x2/9)/(x2-4x2/9)=(2/3)/(1+4/9)-(4/9)/(1-4/9)=6/13+4

因为x²+y²-4x+2y+5=0所以(x²-4x+4)+(y²+2y+1)=0所以(x-2)²+(y+1)²=o所以x=2y=-1所以下面

x+1/x=4=>x=2-3^0.5=>x^2=4x-1;x^2+1=4x=>x^4+x^2/(1+x^2)=(4x-1)^2+x^2/(4x)=16x^2-8x+1+x/4=16(4x-1)-8x+

x=-4y=-3=-516

如果不是9y²,这题不能做如果是9y²的话,你肯定会做自己加上平方吧

X的平方+Y的平方-6X-8Y+25=0,整理就是x²+y²-6x-8y+9+16=0即x²-6x+9+y²-8y+16=0于是（x-3)²+（y-4

x平方-3xy+2y平方/2x平方-9xy+7y平方=[(x/y)-3(x/y)+2]/[2(x/y)-9(x/y)+7]分子分母同时除以y=(4/49-6/7+2)/(8/49-18/7+7)=(4

还有下面这种方法7x平方-y平方分之x平方-2xy+3y平方分子分母同时除以y²=[(x/y)²-2(x/y)+3]/[7(x/y)²-1]=(4/9-4/3+3)/(2

(x+y)/(x-y)=3/2[(x/y)+1]/[(x/y)-1]=3/23(x/y)-3=2(x/y)+2x/y=5y/x=1/5(x^2+y^2)/xy=x/y+y/x=5+1/5=26/5

（6x+2y)/(9x-3y)=6(6x/y+2)/(9x/y-3)=6,解得：x/y=5/12(3x+y)^2/(x^2-y^2)=(3x/y+1)^2/((x/y)^2-1)=(81/16)*(2