已知xy≠0,且x²-2xy-8y²=0,则x分之y=
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3x^2-2xy-8y^2=0,(3x+4y)(x-2y)=03x+4y=0,或,x-2y=03x=-4y,或,x=2yx/y=-4/3,或,x/y=2
(x²+xy-12)²+(xy-2y²-1)²=0由于平方数都大于或等于0,所以上式成立的前提是:(x²+xy-12)²=0,即:x&sup
把他拆成x平方+1/2xy+1/2xy然后利用基本不等式,接下来你应该会做的,我打起来太麻烦
x-5xy+6y=0(√x-2√y)(√x-3√y)=0所以√x=2√y,√x=3√yx=4y或x=9y原式=(8y)/(9y)=8/9或=(14y)/(20y)=7/10
答:x-7y=0x=7y≠0所以:x/y=7,y/x=1/7(x²-3xy+y²)/(2x²﹢xy-3y²)=(x/y-3+y/x)/(2x/y+1-3y/x)
∵x-y=6,xy=4∴(x-y)²=36∴x²-2xy+y²=36∴x²+y²=36+2×4=44两边除以xyx/y+y/x=44/4=11∴xy^
3x²-2xy-8y²=0(x-2y)(3x+4y)=0x=2y或x=-4y/3x/y+y/x=2+1/2=2.5或x/y+y/x=-4/3-3/4=-25/12
xy≠0,所以x≠0,y≠03x²-2xy-8y²=0两边除于xy3(x/y)-2-8(y/x)=0设x/y=t;t≠03t-8/t-2=03t²-2t-8=0(t-2)
x^2-y^2=xy两边同除以xy得:x/y-y/x=1xy^-1-x^-1y=1再问:解分式方程(1)7/2+(900-3x/1.2x)=900/x(2)(100/2a)+1/2=(300/2a)+
是不是x-5√xy-6y=0?(√x-6√y)(√x+√y)=0x>0,y>0则√x+√y>0所以√x-6√y=0√x=6√yx=36y所以√xy=6y所以原式=(36y-12y+y)/(36y+6y
√4x²y²=√(2xy)²=|2xy|=-2xy所以xy
(x+y)(x²-xy-y²)=0,=>x^3-y^3=0,x=y(x²-2xy-5y²)/(x²+2xy+5y²)=-6/8=-3/4=-
Bxyy那么x为正数,因为负数a为任意有理数a^2等于0所以选B
x²-4xy+4y²=0(x-2y)²=0则x=2y,因为xy≠0,则x≠0且y≠=0那么(x-y)/(x+y)=(2y-y)/(2y+y)=y/(3y)=1/3
2X^2+3xy-2y^2=0(2x-y)(x+2y)=0即:2x-y=0或,x+2y=0y=2x或x=-2y当y=2x时:x+y/x-y=3x/(-x)=-3当x=-2y时:x+y/x-y=-y/(
∵x-y=4xy∴原式=[2(x-y)+3xy]/[-(x-y)-2xy]=(8xy+3xy)/(-4xy-2xy)=11xy/(-6xy)=-11/6
∵x2-y2=xy,∴原式=x2y2+y2x2=x4+y4x2y2=(x2−y2)2+2x2y2x2y2=3x2y2x2y2=3.再问:先化简2a+1/a²-1÷a²-a/a
x^2+xy-6y^2=0化简得(x-2y)(x+3y)=0x=2y或x=-3y分别带入2x^2-3xy+y^2/5x^2-7xy+2y^2化简即可.