(x-2y)的8次方 (x-2y)的3次方=多少-搜答案-神马作文网

观察可知分子为(-x)^(2n+1)=-x^(2n+1)分母为y^(2n)所以第六个式子-x^13/y^12第n个式子是-x^(2n+1)/y^(2n)

(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一y)³一8(x一y)²(x+y)+6y(x一y)²]÷2(x一y)²=(x一y)一4(x+y)+3y=x-y-4x-4y+3y=-3x-2y再答：不客

y=x的2次方-6x+8

y=(x-2)(x-4)＜0则2＜x＜4

(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

解题思路：本题目主要考查指数的运算，其中的关键是通过提取负号把y-x转化成-（x-y)解题过程：

-3x的2次方y+4x的2次方y+5x的2次方y-7x的2次方y+1-绝对值8x的2次方y的2次方=(-3+4+5-7)x^2y+1-8x^2y^2=-x^2y-8x^2y^2+1

(x-y)²+3(y-x)=(x-y)²-3(x-y)=(x-y)[(x-y)-3]=(x-y)(x-y-3)

y(x+y)+(x+y)(x-y)-x的2次方,其中X=-2,y=2分之一y(x+y)+(x+y)(x-y)-x的2次方=(x+y)(y+x-y)-x=x(x+y)-x=x(x+y-1)=-2*(-2

10

2的x次方=8的y+1次方2的x次方=2的3（y+1）次方x=3（y+1）=3y+3----------------（1）81的y次方=9的x-5次方3的4y次方=3的2（x-5）次方4y=2（x-5

再答：不客气。

解原式=(x^2+y^2)-(xy)^2=(x^2+xy+y^2)(x^2-xy+y^2)

(x+3y)(x-3y)(x²-9y²）=(x²-9y²)(x²-9y²)=(x²-9y²)²=x^4-18x

把题目写清楚点啊

等量代换,解得等于3

由x的2次方-y的2次方=8得（X+Y）(X-Y)=8X-Y=2所以X+Y=4两式相加X=3Y=1

(x+y)的平方+2*4(x+y)+4的平方(x+y)=(x+y+4)的平方

【(x-y)的3次方-8(x-y)的2次方(x+y)+6y(x-y)的平方】/2(x-y)的平方=(x-y)²[x-y-8(x+y)+6y]/2(x-y)²=1/2（x-y-8x-

(x—y)的2次方×（x—y)的5次方×（y-x)=-(x-y)的2次方×（x-y)的5次方×（x-y)=-(x-y)的(2+5+1)次方=-(x-y)的8次方