作业帮(x²-1)y′+2xy-cosx＝0
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/17 07:30:14
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)
对.前提是x不等于y
(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
xy-1+x-y=XY+X-Y-1(加法交换律）=（XY+X）－（Y＋1）＝X（Y＋1）－(Y+1)（提取公因式X）=(Y+1)(X-1)（提取公因式Y+1）这样可以么?
5x^2y/-1/2xy*3xy^2=-7.5x²y²
(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)=-6xy+3x-3y=-6×(-2)+3×1=15
（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
3/(x-y)=1/xyx-y=3xyy-z=-3xy原式=[(y-x)-2xy]/[2(x-y)+3xy]=[(-3xy)-2xy]/[2(3xy)+3xy]=-5xy/9xy=-5/9
1-x²+2xy-y²=1-(x-y)²=(1-x+y)(1+x-y)x²-y²+x-y=(x-y)(x+y)+(x-y)=(x-y)(x+y+1)
原式(-xy/3)²*[xy(2x-y)-2x(xy-y²)]=(x²y²/9)(2x²y-xy²-2x²y+2xy²)
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=1/2xy-{1/2xy-[1/3x^2y-x^2y+xy]+1/3x^2y}&&去小括号=1/2xy-{1/2xy-[-2/3x^2y+xy]+1/3x^2y}=1/2xy-{1/2xy+2/
（x+2y-3xy)-(-2x-y+xy)=x+2y-3xy+2x+y-xy=(1+2)x+(2+1)y-(3+1)xy=3x+3y-4xy=3(x+y)-4xy=3*1/2-4*(-1/2)=3/2
因为xy/（x+y）=1/2所以x+y=2xy原式=3（x+y)-5xy/(-x-y+3xy)=3*2xy-5xy/(-2xy+3xy)=xy/xy=1
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、(-7x^y)(2x^y-3xy^3+xy)=-14x^(2y)+21x^(y+1)y^3-7x^(y+1)y;2、((x-y)^6)/((y-x)^3)/(x-y)=-(x-y)^3/(x-y)
xy-x-y+1=x(y-1)-(y-1)=(x-1)(y-1)(xy-x-y+1)^2=(x-1)^2(y-1)^2
原式=(x+y)(x+y)+2(x+y)xy+(xy)^2-1^2=(x+y)^2+2(x+y)xy+(xy)^2-1=(x+y+xy)^2-1=(x+y+xy-1)(x+y+xy+1)=(x+y+x
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^_^