若x y=6,x-y=4,求x² y
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第一题应该是.求x^2-y^2和x^2+2xy+y^2的值吧1.∵x^2+xy=6y^2+xy=4∴两式相减得x^2-y^2=2两式相加得x^2+2xy+y^2=102.∵若x=1时代数式ax^2+b
x^+2xy+y^+4=16(x+y)²=16-4=12(1)x^-2xy+y^=16(x-y)²=16(2)(1)-(2)2y*2x=-4xy=-1(3xy+6y^)+|x^-(
2x+3y-3xy+(4xy-3x)-(4y-7)=2x+3y-3xy+4xy-3x-4y+7=-x-y+xy+7=-6-6+2+7=-3
首先化简:原式=7x+4y+xy-5y-6x+6xy=(x-y)+7xy因为,x-y=5,-xy=3所以原式=5-21=-16楼上忘记加负号了~
你好:原式=(7x+4y+xy)-(5y+6x-6xy)……………………把“6”乘进去=7x+4y+xy-5y-6x+6xy=x-y+7xy因为x-y=5,-xy=3所以xy=-3所以,原式=5+7乘
x=-1,y=-6或x=6,y=1代入式子得x^2-xy^2=37或30x^2y+xy^2=-42或42
1/x+1/y=5两边乘以xy得y+x=5xy∴x+y=5xy3x+4xy+3y/x+3xy+y=[3(x+y)+4xy]/[(x+y)+3xy]=(15xy+4xy)/(5xy+3xy)=19xy/
(x+y)^2=36x^2+y^2+2xy=36x^2+y^2=36-2*2.75=30.5(x-y)^2=x^2+y^2-2xy=30.5-2*2.75=25x-y=5或者-5已知x-y>0x-y=
(x*x+y*y)(x*x+y*y)-4x*x*y*y=(x^4-2x^2y^2+y^4)=(x^2-y^2)^2=0x^2=y^2x/y=±1(x*x+5xy+y*y)/(x*x+2xy+y*y)=
(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)=-2xy+2x+3y-3xy-2y+2x-x-4y-xy=-6xy+3x-3y=-6xy+3*(x-y)当时,原式=-6*1+3*
2x+y+6=xy化简得:Y=(2X+6)/(X-1)X不等于0因为正实数x.所以X>0所以X>1函数Y=(2X+6)/(X-1)是单调递增所以X=2为最小值,Y=10所以XY最小值为XY=20
先把代数式(5XY+4X+7Y)+(6X-3XY)-(4XY-3Y)化简(5XY+4X+7Y)+(6X-3XY)-(4XY-3Y)=5XY+4X+7Y+6X-3XY-4XY+3Y=-2XY+10X+1
把第一个式子分开来看,x的平方-8x+16+y的平方+6Y+9=0,然后就有两个完全平方了,(x-4)的平方+(y+3)的平方=0然后可以得出x=4,y=-3,然后带进去就可以得出答案
(7x+4y+xy)-6(5/6y+x-xy)=7x+4y+xy-5y-6x+6xy=x-y+7xy=5+7×(-3)=-16
把括号打开7X+4Y+XY-5Y-6X+6XY=X-Y+7XY=5+7*(-3)=-16
(7x+4y+xy)-6(六分之五y+x-xy)=7x+4y+xy-5y-6x+6xy=x-y+10xy把x-y=5和-xy=3代入x-y+10xy=5+10*(-3)=5-30=-25所以原式的值是
已知x+xy=-2,xy-y=-6则X+Y=42x{-4y-3[(x+xy)²+x]-½[(y-xy)²-2y]=2x{-4y-3[(-2)²+x]-&fr
得y-x=3xyx-y=-3xy原式=-15xy+2xy/-3xy-4xy=-13/-7=13/7
x^2y+xy^2=xy×(x+y)=6×5=30