数学题 求解.要的是过程

Question

数学题 求解.要的是过程

Answer 1

【参考答案】

1、原式=[(x+2y)/(x+y)]×[xy/(x+2y)]÷[(x+y)/(xy)]
=[xy/(x+y)]×[xy/(x+y)]
=x²y²/(x+y)²

2、原式=(1/a +1/b)²Ã·[(1/a +1/b)(1/a -1/b)]
=(1/a +1/b)÷(1/a -1/b)
=[(a+b)/(ab)]÷[(b-a)/(ab)]
=(b+a)/(b-a)

3、原式=[(9x^4)/(16y²)]×[2y/(3x)]+[x³/(4y^4)]
=[3x³/(8y)]+[x³/(4y^4)]
=[3x³y³/(8y^4)]+[2x³/(8y^4)]
=(3x³y³+2x³)/(8y^4)

4、原式=[(a+b)²/(a-b)²]×(2/3)[(a-b)/(a+b)]-[ab/(a²-b²)]
=(2/3)[(a+b)/(a-b)]-[ab/(a²-b²)]
=[(2/3)(a+b)²/(a²-b²)]-[ab/(a²- b²)]
=(2/3 a²+ 2/3 b²- 1/3 ab)/(a²-b²)

Answer 2

(1),
[x/(x+y)+2y/(x+y)]*xy/(x+2y)/(1/x + 1/y)
=(x+2y)/(x+y) * xy/(x+2y)/[(x+y)/xy] …………约分
=1
(2).
(1/a+1/b)^2/[(1/a^2) -(1/b^2)]
=[(a+b)^2/(ab)^2]*[(ab)^2/(b^2-a^2)]
=(a+b)^2/(b^2-a^2)
=(b+a)/(b-a)
(3).
(3x^2/4y)^2 *2y/3x+(x^2/2y^2)/(2y^2/x)
=x^3(2y^3+2)/8y^4…………通分
(4).
[(a+b)/(a-b)]^2*(2a-2b)/(3a+3b)-[a^2/(a^2-b^2)]/(a/b)
=2/3*(a+b)/(a-b)-ab/(a+b)(a-b)
=(2a^2+ab+2b^2)/3(a+b)(a-b)

Answer 3

这个怎么帮你打啊 很简单的说