xy-[2x 5x-1]-[xy-2 3x 1]-搜答案-搜搜做题作业网

4x^2-4xy-a^2+y^2=(2x-y)^2-a^2=(2x-y-a)(2x-y+a)x^2-2y-4y^2+x=(x+1/2)^2-(2y+1)^2=(x-2y-1/2)(x+2y+3/2)5

xy(xy+1)+(xy+3)-2(x+y+1/2)-(x+y-1)^2=xy(xy+1)+(xy+1)+2-2(x+y)-1-[(x+y)^2-2(x+y)+1]=(xy+1)^2+2-2(x+y)

1/2≥(2/xy)^2==》√2/2≥|2/xy|==》√2≤|xy/2|==》2√2≤|xy|==》xy≤-2√2或2√2≤xy

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

(x+y-2xy)(x+y-2)+(1-xy)^2=(x+y)^2-2(1+xy)(x+y)+4xy+1-2xy+x^2y^2=(x+y)^2-2(1+xy)(x+y)+(1+xy)^2=(x+y)^

3xy[2xy-x(y-2)+x-1]=3xy(2xy-xy+2x+x-1)=3xy(xy+3x-1)=3x^2y^2+9x^2y-3xy

xy²+2xy-x=x(y²+2y-1)=x(y²+2y+1-2)=x[(y+1)²-2]=x(y+1+√2)(y+1-√2)再问：太厉害啊，那再做多两题吧，也

5x^2y/-1/2xy*3xy^2

5x^2y/-1/2xy*3xy^2=-7.5x²y²

解(x+1)平方+/y-1/=0∴x+1=0,y-1=0∴x=-1,y=1∴2(xy-5xy平方)-(3xy平方-xy)=(2xy+xy)+(-10xy平方-3xy平方)=3xy-13xy平方=3×(

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

这个是原题要求的吧|x|/x+|y|/y+|xy|/xy（1）xy>0x,y都大于零或都小于零x,y都大于零时|x|/x+|y|/y+|xy|/xy=|x|/x+|y|/y+|xy|/xy=x/x+y

（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

因式分解xy²-2xy+x+2y-1解xy²-2xy-y²+x+2y-1=xy²-2xy+x-y²+2y-1=x(y²-2y+1)-(y&#

原式=1-3xy+x+(-4x-6xy)=1-3xy+x-4x-6xy=1-3x-9xy

3xy-3xy-xy+2yx

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：

-1/3(xy+3)^2+3(3-xy)^2=（-1/3）[(xy+3)²-9(3-xy)²]=(-1/3)(xy+3+3(3-xy))(xy+3-3(3-xy))=(-1/3)(

[(xy-2)(-xy-2)-4(xy-1)^2]除以(-xy)=[-x²y²+4-4(x²y²-2xy+1)]÷(-xy)=(-x²y²+

再答：望采纳，谢谢！可以继续追问哟^_^再问：过程再答：好的，马上哈再答：再答：就是合并同类项的意思再答：再答：好的，谢谢哈^_^