已知x加y加2=2xy,则4x-5xy加4y加8=[]xy
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X+Y=5,XY=2,5X+4Y-3X-2Y+XY=2X+2Y+XY=2(X+Y)+XY=2×5+2=12.
(2X-3Y-2XY)-(X-4Y+XY)=2X-3Y-2XY-X+4Y-XY=X+Y-3XY因为x加y等于110,xy等于33所以原式等于:110-33*3=11
原式=(x+2y)^2-(x+2y)+1/4=0则x+2y=1/2
xy分之x加y等于2∴x+y=2xy3x减5xy加3y分之负x加3xy减y=[-(x+y)+3xy]/[3(x+y)-5xy]=(-2xy+3xy)/(6xy-5xy)=xy/(xy)=1
x^2+y^2-4x-10y+29=0x^2-4x+4+y^2-10y+25=0(x-2)^2+(y-5)^2=0x=2y=5x^y+xy^2=xy(x+y)=2*5(2+5)=70
已知x平方加xy等于8,y平方加xy等于9,则x平方加y平方加2xy值是8+9=17
x平方加y平方减2xy减6x加6y加9=0x^2+y^2-2xy-6x+6y+9=0(x^2+y^2-2xy)-6(x-y)+9=0(x-y)^2-6(x-y)+9=0(x-y-3)^2=0x-y-3
直接设X=1,Y=0.5.带入后式得出10
x²+2xy+4y²+x²y²+1=8xy(x²-4xy+4y²)+(x²y²-2xy+1)=0(x-2y)²
x方+y方+5/4=2x+y(x方-2x+1)+(y方-y+1/4)=0(x-1)方+(y-1/2)方=0x=1,y=1/2xy/(x+y)=1/3
此题简单做法你直接可以设X=1,Y=0.5,使其满足前面的条件即可,带入后面分式,后面的式子中文表述不清,
∵xy/x+y=2∴xy=2(x+y)=2x+2y4x加3xy加4y分之9x减2xy加9y=(9x-2xy+9y)/4x+3xy+4y)=(9x+9y-4x-4y)/(4x+4y+6x+6y)=(5x
2x【的平方】+4x+y的平方=2xy-42x的平方-2xy+4x+y的平方+4=0x的平方-2xy+y的平方+x的平方+4x+4=0(x-y)^2+(x+2)^2=0x-y=0,x=yx+2=0,x
x^2减6xy加9y等于0.则x:y等于_3:1___.
已知xy/(x+y)=2,求:(3x-5xy+3y)/(-x+3xy-y)xy/(x+y)=2得:xy=2(x+y)(3x-5xy+3y)/(-x+3xy-y)=(3x-9xy+3y+4xy)/(-x
2x²-3xy+y²=0(2x-y)(x-y)=0所以x=y或者2x=y当x=y时,x/y+y/x=1+1=2当2x=y时,x/y+y/x=1/2+2=5/2
xy分之【x加y】等于2分之一xy=2(x+y)【xy加x加y】分之xy=2(x+y)/[2(x+y)+x+y]=2(x+y)/[3(x+y)]=2/3
∵x的平方加xy等于负5,xy加y的平方等于9∴x的平方减y的平方=(x²+xy)-(xy+y²)=-5-9=-142x的平方加3xy加y的平方=2(x²+xy)+(xy