2道初一分式的题~~求过程~~!~~ 快~~~3-x/2x-4÷(x+2 - 5/x-2)(1/x+1 + 1/x-1)÷ x/x+1

问题描述:

2道初一分式的题~~求过程~~!~~ 快~~~
3-x/2x-4÷(x+2 - 5/x-2)
(1/x+1 + 1/x-1)÷ x/x+1

题目中式子表达得不够规范,下面是比较标准的式子:
(3-x)/(2x-4)÷(x+2-5/(x-2))
= (3-x)/(2x-4)÷((x^2-4)/(x-2)-5/x-2))
= (3-x)/(2x-4)÷(x^-9)/(x-2)
=(3-x)/(2x-4)×(x-2)/(x^2-9)
=(3-x)/2(x-2)×(x-2)/(x-3)(x+3)
=1/(2x+6)
第二个分式应为:
( 1/(x+1)+ 1/(x-1) )÷x/(x+1)
=((x-1)/((x-1)(x+1))+(x+1)/((x-1)(x+1)))×(x+1)/x
=2x/((x+1)(x-1))×(x+1)/x
=2/(x-1)