x y=2,xy=-1,x的六次方 y的六次方=?
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x-xy=8(1)xy-y=-9(2)则有(1)-(2):X-XY-XY+Y=X+Y-2XY=8-(-9)=17
=-x-(2y-2+3x)+2(x+4)=-x-2y+2-3x+2x+8=-4x-2y+10
1.2(Xy+Xy)-3(Xy-xy)-4Xy=2*2xy-0-4xy=4xy-4xy=02.1/2ab-5aC-(3acb)+(3aC-4aC)=1/2ab-5ac-3acb-ac=1/2ab-6a
(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)=-6xy+3x-3y=-6×(-2)+3×1=15
3xy-[2xy-2(xy-2分之3xy)+xy]+3xy=6xy-[2xy-2xy+3xy+xy)=6xy-4xy=2xy=2×3×3分之1=2
原式=3x-3y-6xy=3-12=-9
1、求值:4x的2次幂y-【6xy-2(4xy-2)-x的2次幂】+1,其中x=-2分之1=4x²y-(6xy-8xy+4-x²)+1=4x²y+2xy-4+x²
4A=12x^2+20xy-12y-43B=12x^2+6xy-34A-3B=14xy-12y-1=y(14x-12)-1与y无关,即14x-12=0x=12/14=6/7
(1)∵xy+x=-1①,xy-y=-2②,∴①-②得x+y=1;(2)先把xy+x=-1,xy-y=-2的值代入代数式,得原式=-x-[2y-1+3x]+2[x+4]=-x-2y+1-3x+2x+8
=3x^2y-2xy^2+2(xy-3/2x^2y)-xy+3xy^2=3x^2y+xy^2+2xy-3x^2y-xy=xy+xy^2=3*(-1/3)+3*1/9=-2/3
Ⅰx-1Ⅰ≥0且x+y-2的2次幂≥0又Ⅰx-1Ⅰ+【x+y-2的2次幂】=0所以Ⅰx-1Ⅰ=0且x+y-2的2次幂=0x-1=0且x+y-2=0所以x=1,y=1xy=1
[(3x的2次幂y+2xy的2次幂)除以xy]的2次幂=(3x+2y)²=9x²+12xy+4y²
(-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*
其次指各项变量的幂次相同例子的幂次都是2
令x=0,y=-1代入原式得值为1,选C
原式=3x的2次方y/(-1/2xy)-xy的2次方/(-1/2xy)+1/2xy/(-1/2xy)=-6x+2y-1
-x^5y-(2a+b)xy^3-212a+b=0,a=-b/2
3次多项式常数项是-1
5x²+5xy+y²+2x+1=04x²+y²+4xy+2x+x²+1=0(2x+y)²+(x+1)²=0得{2x+y=0---①
(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)=-2xy+2x+3y-3xy-2y+2x-x-4y-xy=-6xy+3x-3y=-6*(-2)+3*1=15不懂可追问,有帮助请采