Question

约分： 2xy-4y/x-2 a²-ab/a²-b² x²-9/9-6x+x²

4-8b/4b²-1
化简：
（x+y）²/x²-y平方
要过程
(1)2xy-4y/x-2
(2)a²-ab/a²-b²
(3)x²-9/9-6x+x²

Answer 1

2xy-4y/x-2 =2y(x-2)/(x-2)=2y
a²-ab/a²-b²=a(a-b)/(a+b)(a-b)=a/a+b
x²-9/9-6x+x²=(x+3)(x-3)/(x-3)²=x+3/x-3
4-8b/4b²-1=4(1-2b)/(2b+1)(2b-1)= -4(2b-1)/(2b+1)(2b-1)= -4/2b+1
(x+y)²/x²-y²=(x+y)²/(x+y)(x-y)=x+y/x-y

Answer 2

2xy-4y/x-2=2y（x-2）/x-2=2y

a²-ab/a²-b²=a(a-b)/(a-b)(a+b)=a/a+b

x²-9/9-6x+x²=(x-3)(x+3)/(x-3)²=x+3/x-3

4-8b/4b²-1=-2(2b-1)/(2b-1)(2b+1)

（x+y)²/x²-y²=（x+y)²/（x+y)（x-y)=（x+y)/（x-y)

Answer 3

2xy－4y／x－2=y(2x﹣4)／x－2=2y