求x的平方 4y平方的值求x分之一 2y分之一的值
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x^2-y^2=(x+y)(x-y)30=4/3*(x-y)x-y=30*3/4x-y=45/2
若y=根号[(x^2-2)/(5x-4)]+[根号(x^2-2)/(4-5x)]+2[(x^2-2)/(5x-4)]>=0(x^2-2)/(4-5x)]>=0两个相反数同时大于或等于0,两个必须都为0
(1)x^2+3xy-4y^2=0十字相乘:(x+4y)(x-y)=0则:x=-4y,或x=y;当x=-4y时,(x-2y)/(x+2y)=-6y/(-2y)=3;当x=y时,(x-2y)/(x+2y
原式=(x^2-2x+1)+(y^2-4y+4)=(x-1)^2+(y-2)^2=0,所以x=1,y=2,代入问题得结果为3/2
x平方)+(y平方)-4x-6y+13+0可化为(x-2)^2+(y-3)^2=0x=2,y=3代入原式=(9-4)/6=5/6
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
注意到所求式上下是齐次的(都是二次)因此将y=3x或y=-3x代入得结果是10/13或16/7说错了应该反一反答案是对的
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/
(x平方+y平方)平方-y平方=x平方+6所以(x²+y²)²-(x²+y²)-6=0(x²+y²+2)(x²+y
设x/2=y/3=z/4=k∴x=2k,y=3k,z=4k∴(xy+yz+zx)/(x²+y²+z²)=(6k²+12k²+8k²)/(4k
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=1/2y=2x(x^2+2xy+y^2)/(x^2-xy+y^2)=(x^2+2x*2x+(2x)^2)/(x^2-x*2x+(2x)^2)=9x^2/3x^2=3
y分之x=2分之1y=2x所以原原式=(x²-2x²-8x²)分之(x²+4x²+4x²)=-9分之9=-1
令3分之x=4分之y=6分之z=kx=3k,y=4kz=6k(xy+yz+xz)/(x^2+y^2+z^2)=k^2(12+18+24)/k^2(36+16+9)=54/61
x+7y=y-3x4x=-6yy=-2x/3所以y²=4x²/9所以原式=(x²+4x²/9)/(x²-4x²/9)=(13x²/
x=5y所以原式=(25y²-10y²+3y²)/(100y²+25y²-6y²)=18y²/119y²=18/119
3∵x/y=1/2∴y=2x故(x^2+2xy+y^2)/(x^2-xy+y^2)=(x+y)^2/(x^2-xy+y^2)=(x+2x)^2/(x^2-x·2x+4x^2)=9x^2/(3x^2)=
y分之x=2分之1y=2x所以原原式=(x²-2x²-8x²)分之(x²+4x²+4x²)=-9分之9=-1
X平方+4Y的平方=4XYx^2-4xy+4y^2=0(x-2y)^2=0x=2yX-Y分之X+2Y=(2y+2y)(2y-y)=4y/y=4