作业帮② 5(x+y)3-2(x-y)4-2(x+y)3+(y-x)4
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/28 21:29:27
1.x+y+z2.-x-3y-1
(2x-y)(3x-2y)+(y-x)(2x-5y)＝6x²-4xy-3xy+2y²+2xy-5y²-2x²+5xy=4x²-3y²
原式=(9x²+24xy+16y²-4x²+y²-5x²+6xy-y²)÷(-2y)=(30xy+16y²)÷(-2y)=-15x
原式=(x²+4xy+4y²-3x²-2xy+y²-5y²)÷2x=(-2x²+2xy)÷2x=-x+y再问：x=-2y=二分之一再答：=5
-x^y^7+y^8)(这里有问题,x的几次方?再问：就是一次方再答：(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-xy^7+y^8)(x^2+xy+y^2)=（x^8-x^7y+x^
设x-y=mx+y=n则6m-2n=143m+n=5解得m=2n=-1即x-y=2x+y=-1解得x=1/2y=-3/2
化简得：-x+7y=11①7x+3y=27②①式×7得：-7x+49y=77③②+③得：52y=104∴y=2代入①得：x=3∴x=3,y=2再问：亲，是代入法哦！再答：代入法①式得3x+3y-4x+
2(2x+3y)(3x+2y)-(6x-y)(2x-5y)=12x^2+26xy+12y^2-(12x^2-32xy+5y^2)=12x^2+26xy+12y^2-12x^2+32xy-5y^2=58
（x+2)(x+3)=x²+5x+6(x-4)(x+1)=x²-3x-4(y+4)(y-2)=y²+2y-8(y-5)(y-3)=y²-8y+15x²
[(x+2y)(x-2y)-(2x-y)^2+(3x-y))2x-5y)]/(-x)=(x²-4y²)-(4x²-4xy+y²)+(6x²-17xy+
因为(x-y)/(x+y)=3,则(x＋y)/(x－y)＝1/3则5(x-y)(x+y)-(x+y)/2(x-y)＝5*3-1/(3*2)=15-1/6=89/6
(x-y)^5*(y-x)^3*(x-y)^2=-(x-y)^5*(x-y)^3*(x-y)^2=-（x-y）^(5+3+2)=-(x-y)^10
=(x+y)(6-16)+(x-y)(2-5-1)=-10(x+y)-4(x-y)再问：能讲过程吗？谢谢！再答：先把(x+y)提出来，在把(x-y)提出来
/>(2x-y)(3x-2y)+(y-x)(2x+5y)=6x²-3xy-4xy+2y²+5y²-2x²+5xy-2xy=6x²-2x²-7
解(x-y)(x+y)-(x-2y)²+x(3x-5y)-(x-y)(x-2y)=(x²-y²)-(x²-4xy+4y²)+(3x²-5xy
原式=(5-8)(x-y)^2-(1+3)(x-y)=-3(x-y)^2-4(x-y)
[(x+2y)^2-(x+y)(3x-y)-5y^2]/2x=[x^2+4xy+4y^2-3x^2-2xy+y^2-5y^2]/2x=(-2x^2+2xy)/2x=y-x
(2X-3y)-(5x-y)=2x-3y-5x+y=2x-5x-3y+y=(2x-5x)+(-3y+y)=-3x-2y这样写总是全过程了吧