y-x-2=0 x2 y2=1
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xy/x+y=1/3x+y=3xyx2y2/x2+y2=1/5(xy)²/[(x+y)²-2xy]=1/5(xy)²/[(3xy)²-2xy]=1/5(xy)&
∵(x2+4y2)2-16x2y2=0(x2+4y2+4xy)(x2+4y2-4xy)=0(x+2y)2(x-2y)2=0∴x+2y=0,x-2y=0∴y=-12x或y=12x.
x2y2-20xy+x2+81=(xy-10)2+x2-19=0则xy-10=0且x2-19=0得x=+-根号19y=+-10/根号19对于像这种未知数个数多于方程类型的式子,如果能求解,只有一种情况
x3y+2x2y2+xy3=xy(x2+2xy+y2)=xy(x+y)2,∵x+y=5,∴(x+y)2=25,x2+y2+2xy=25,∵x2+y2=13,∴xy=6,∴xy(x+y)2=6×25=1
∵x+y=4,∴(x+y)2=16,∴x2+y2+2xy=16,而x2+y2=14,∴xy=1,∴x3y-2x2y2+xy3=xy(x2-2xy+y2)=14-2=12.
x3次方y-2x2y2+xy3=xy(x²-2xy+y²)=xy(x-y)²=3x3²=27如果本题有什么不明白可以追问,再问:=xy(x2-2xy+y2)=x
(2x4-4x3y-x2y2)-2(x4-2x3y-y3)+x2y2=2x4-4x3y-x2y2-2x4+4x3y+2y3+x2y2=2y3,因为化简的结果中不含x,所以原式的值与x值无关.
原式=(x^4-2x²y²+y^4)+6xy(x²+2xy+y²)-2xy(x+y)=(x²-y²)²+6xy(x+y)²
变形得:x2+2x+1+x2y2-2xy+1=0,∴(x+1)2+(xy-1)2=0,∴x+1=0xy−1=0,解得:x=−1y=−1,∴x+y=-2,故选B.
由x²+y²-4x-10y+29=0得(x-2)²+(y-5)²=0所以x=2y=5所以x²y²+2x^3*y²+x^4*y&su
解题思路:圆的参数方程解题过程:varSWOC={};SWOC.tip=false;try{SWOCX2.OpenFile("http://dayi.prcedu.com/include/readq.
原式=2x2y-2xy2-[-3x2y2+3x2y+3x2y2-3xy2]=2x2y-2xy2+3x2y2-3x2y-3x2y2+3xy2=2x2y-3x2y-2xy2+3xy2+3x2y2-3x2y
x+y=4,xy=2后者平方后二式相加再加后者平方
由x2+y2=2x,得y2=2x-x2≥0,∴0≤x≤2,x2y2=x2(2x-x2)=2x3-x4.设f(x)=2x3-x4(0≤x≤2),则f′(x)=6x2-4x3=2x2(3-2x),当0<x
.24、二次函数y=-2x2+4x-3的图象的开口向;顶点是.25、1、将-x4+x2y2因式分解正确的是()A、-x2(x2+y2)B、-x2(
(2X²-2y²)-3(X²y²+X²)+3(X²y²+y²)=2x²-2y²-3x²y&
∵x-y=l,xy=2,∴x3y-2x2y2+xy3=xy(x2-2xy+y2)=xy(x-y)2=2×1=2.
因为x²+4y²+x²y²-6xy+1=0(x²-4xy+4y²)+(x²y²-2xy+1)=0(x-2y)²