搜搜考试网4 12(x-y) 9(x-y)的二次方
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x+x+x+y+y=54,x+x+y+y+y=56得出3X+2Y=54,2X+3Y=56扩大后得出6X+4Y=108,6X+9Y=118两式相减得出Y=2得出X=50/3
6*(x+y)^7-9*(x+y)^3*(x-y)^2*((3*x-3*y)*(x+y))^(1/2)ok?再问：可不可以写清楚点
原式=(x-3y)²-3(x-3y)=(x-3y)(x-3y-3)再问：用因式分解再答：对啊，没错再问：好吧
25(x+y)的平方-9(x-y)的平方=[5(x+y)+3(x-y)][5(x+y)-3(x-y)]=(8x+2y)(2x+8y)=4(4x+y)(x+4y)
(x-y)(z+y-x+y+2y)÷4y=(x-y)(z-x+4y)÷4y{(x+y)(x-y)-(x-y)的2次方+2y(x-y)}除以4y=(x-y)(x+y-x+y+2y)÷4y=(x-y)(4
∵2x-y/x+2y=3∴2(2x-y)/x+2y-9(x+2y)/2x-y+3＝2×3-9×1/3+3=6
原式=(x-y)[(x-y)^2-6(x-y)+9]=(x-y)(x-y-3)^2很高兴为您解答,祝你学习进步!不懂可追问!
∵x²+y²-4x+2y+5=0x²-4x+4+y²+2y+1=0(x-2)²+(y+1)²=0x-2=0y+1=0∴x=2y=-14x&#
2x+y=6x+2y=9相加得3x+3y=15x+y=5相减得2x+y-x-2y=6-9x-y=-3
4-12(x-y)+9(x-y)²=[2－3﹙x－y﹚]²=﹙2－3x＋3y﹚²再问：那个小的2是怎么弄的再答：二次方，就是平方
这是完全平方原式=[3(x-y)]²+2×[3(x-y)]×2+2²=[3(x-y)+2]²=(3x-3y+2)²
x/(x+y)(x--)^3=x/(x+y)(x--y)^3y/(y+x)(y--x)^2=y(x--y)/(x+y)(x--y)^3.
(x-y)^3+9(x-y)-6(x-y)^2=(x-y)[(x-y)^2-6(x-y)+9]=(x-y)[(x-y)-3]^2=(x-y)(x-y-3)^2
区域是一个正方形
5x=3y,x=3y/5(2x+y)的平方=5x(x+y)+94x²+4xy+y²=5x²+5xy+9x²+xy-y²+9=09y²/25+
(x+3y)(x-3y)(x²-9y²）=(x²-9y²)(x²-9y²)=(x²-9y²)²=x^4-18x
第一项与第三项先合并9xy(x-y)(x+1)-3y(x-y)(3x+2y)+6y^2*(x-y)(x+1)=(x-y)(x+1)(9xy+6y^2)-3y(x-y)(3x+2y)=(x-y)(x+1
(x+y)(x+y)=25x^2+2xy+y^2=25……(1)(x-y)(x-y)=9x^2-2xy+y^2=9……（2）（1）+（2）得：2x^2+2y^2=34x^2+y^2=17(1)-(2)
9(x-y)的平方+3x-3y=9(x-y)的平方+3(x-y)=3(x-y)[3(x-y)+1]=3(x-y)(3x-3y+1)
判断X的数值是否大于Y的数值如果是则为真等式去X的值反之取Y的值