(x y)^2-18(x y) 81怎么算
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xy²-2xy+2y-4=xy(y-2)+2(y-2)=(y-2)(xy+2)
1=(x-z-2ab)/xy2=(a²-2ab+b²)/a-b=(a-b)²/a-b=a-
1/2≥(2/xy)^2==》√2/2≥|2/xy|==》√2≤|xy/2|==》2√2≤|xy|==》xy≤-2√2或2√2≤xy
3xy是3x原式=(x-3y)(x+2y)+3x+y+2十字相乘x-3y2×x+2y1所以原式=(x-3y+2)(x+2y+1)
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
对.前提是x不等于y
5x^2y/-1/2xy*3xy^2=-7.5x²y²
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
=xy-3xy+2xy-xy=-xy
∵xy=2,∴x=2y,则原式=(2y)2−2y•y+3y2(2y)2+2y•y+6y2=4y2−2y2+3y24y2+2y2+6y2=512.
xy(y-2)+2(y-2)下步不写了能看懂吧?
-3(2x^2-xy)+4(x^2+xy-6)=-6x^2+3xy+4x^2+4xy-24=-2x^2+7xy-24再问:thankyou~
(3x^2+2xy)/xy-(2x^2-xy)/xy=(3x^2+2xy-2x^2+xy)/xy=(x^2+3xy)/xy=x(x+3y)/xy=(x+3y)/y
-xy^2+2xy-x=-x(y^2-2y+1)=-x(y-1)^2如果本题有什么不明白可以追问,如果满意请点击“选为满意答案”
由题意得:X=Y+2.那么Y(Y+2)+Y+2=20(Y+2)×(Y+1)=20所以y=3那么x=5可待入xy+y=18就不对了.(Y+2)×(Y+1)=20,Y应该是-6,X是-4,答案就对了.X=
3xy-3xy-xy+2yx=-xy+2xy=xy
=(x²y²-4-x²y²-xy+4)/(-2xy)=-xy/(-2xy)=1/2
y^3+xy^2+2xy+x^2-1=(x+y-1)(x+y^2+y+1)再问:烦写出过程再答:
得0=(-X+X)y=0×y=0