搜搜考试网3x-y-3(20-x-y)怎么解
来源：学生作业帮助网 编辑：作业帮 时间：2024/06/03 16:48:28
原式=-(x-y)³(x-y-1)
(x-y)^2-(x-y)^3=(x-y)^2[1-(x-y)]=(x-y)^2(1-x+y)2.（x+y）^2-（x+y）^3=（x+y)^2[1-(x+y)]=(x+y)^2(1-x-y)3、（x
由(1)得3x+3y+2x-2y=365x+y=36(3)由(2)得4x+4y-3x+3y=-20x+7y=-20(4)(3)×7-(4)得34x=272∴x=8把x=8代入(3)得y=-4∴x=8y
(3x+y)(3x-y)=9x²-3xy+3xy-y²=9x²-y²
{(x+y)/2+(x-y)/3=63(x+y)+2(x-y)=36(1)4(x+y)-3(x-y)=-20(2)由（1）*3+(2)*2得9(x+y)+6(x-y)+8(x+y)-6(x-y)=36
(x+y)(x+y)^2(-x-y)^3=－(x+y）^6
(y-x)(x-y)^3(y-x)^5=(y-x)[-(y-x)^3](y-x)^5=-(y-x)^(1+3+5)=-(y-x)^9=(x-y)^9
(x+y)-(2x+y/2)-(3x+y/6)-(4x+y/12)-(5x+y/20)-……-(10x+y/90)=x-2x-3x-4x-..-10x+y*(1-1/2-1/6-1/12-..1/90
X+Y分之X-Y等于3x=-2yX+Y分之2(x-y)减X+Y分之3X+Y=(-x-3y)/(x+y)=1
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-2y)*(3x-y)=-3x^2-5xy+2y^2
(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
第二个方程是不是写错了2/（x+y）+3/（x-y）=6是这样吗
(x-3y)(x+y)-(x-2y)(x+2y)-(x-y)平方=x²-2xy-3y²-x²+4y²-x²+2xy-y²=(x²-
=(x-y)[(3x+y)-(2x+3y)]*(x-y)=(x-y)*(x-y)(3x+y-2x-3y)=(x-y)(x-y)(x-2y)到底是化简,还是?=(x*x-2xy+y*y)(x-2y)=x
解题思路：根据题意，由整式的运算的知识整理，分析可以求得解题过程：
解代数式得：-3x的平方y-2y的三次方因为1/2的平方=-1/2的平方,所以结果仍正确给分吧!嘿嘿!
(X+Y-3)(X-Y+3)=[X+(Y-3)][X-(Y-3)]=X²-(Y-3)²
(x+y)^2-3(x+y)=(x+y)(x+y-3)
(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