神马作文网5x+2y＝25.2,2.5x-y=0.4
来源：学生作业帮助网 编辑：作业帮 时间：2024/11/11 20:04:01
(2x-y)(3x-2y)+(y-x)(2x-5y)＝6x²-4xy-3xy+2y²+2xy-5y²-2x²+5xy=4x²-3y²
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^2=x的平方‘/’为除以[(x+2y)^2-(x+y)(x-y)-5y^2]/(2x)=[(x^2+4xy+4y^2)-(x^2-y^2)-5y^2]/(2x)=[4xy]/(2x)=2y[(3x
5x平方+8xy-4y平方
(x-y)的2次方-2(x-y)+(x-y)-5(x-y)=(x-y)²-2(x-y)+(x-y)-5(x-y)=(x-y)²-(x-y)-5(x-y)=(x-y)²-6
2（x+2y）＝x²+y²+5整理得(x-1)^2+(y-2)^2=0x=1,y=2(x²+y²)/(3x-4y)=-1
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+
1)x(x-y)(x+y)-x(x+y)^2=x((x-y)(x+y)-(x+y)^2)=x(x^2-y^2-x^2-2xy-y^2)=x(-2xy-2y^2)=-2xy(x+y)2)（2a+b)(2
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
/>(2x-y)(3x-2y)+(y-x)(2x+5y)=6x²-3xy-4xy+2y²+5y²-2x²+5xy-2xy=6x²-2x²-7
1)(2x+5y)(2x-5y)(-4x^2-25y^2)=-(4x^2-25y^2)(4x^2+25y^2)=-(16x^4-625y^4)=625y^4-16x^42)[（x+y)(x-y)-(x
绝对值加平方=0因为两者均大于等于0所以都是0|x+y+2|=0(2x+3y+5)²=0x+y=-22x+3y=-5x=-1y=-1有什么不明白可以继续问,随时在线等.
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)
你的题目不够清楚,分子和分母请用括号括起来再问：请快点回答?[x-y/2x]+[y/2x][5/x-5]+[x/5-x][5x/x²2xy+y²]-[5y/x²2xy+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