早教吧作业答案频道 -->数学-->
数学题152解方程：1/(x+5)+1/(x+8)=1/(x+6)+1/(x+7),
题目详情
数学题152
解方程：1/(x+5)+1/(x+8)=1/(x+6)+1/(x+7),
解方程：1/(x+5)+1/(x+8)=1/(x+6)+1/(x+7),
▼优质解答
答案和解析
1/(x+5)+1/(x+8)=1/(x+6)+1/(x+7)
通分
(2x+13)/(x+5)(x+8)-(2x+13)/(x+6)(x+7)=0
(2x+13)[1/(x^2+13x+40)-1/(x^2+13x+42)]=0
x^2+13x+40不等于x^2+13x+42
所以1/(x^2+13x+40)-1/(x^2+13x+42)不等于0
所以2x+13=0
x=-13/2
经检验,x=-13/2是方程的根
通分
(2x+13)/(x+5)(x+8)-(2x+13)/(x+6)(x+7)=0
(2x+13)[1/(x^2+13x+40)-1/(x^2+13x+42)]=0
x^2+13x+40不等于x^2+13x+42
所以1/(x^2+13x+40)-1/(x^2+13x+42)不等于0
所以2x+13=0
x=-13/2
经检验,x=-13/2是方程的根
看了 数学题152解方程：1/(x...的网友还看了以下：