x-0.8x=1.2解方程 解方程1/(x^2+x-2)+1/(x^2+7x+10=2

解方程1/(x^2+x-2)+1/(x^2+7x+10=2  

解方程1/(x^2+x-2)+1/(x^2+7x+10=2

就是分式分解：
1/(n+a)(n+b)=1/(b-a)[1/(n+a)-1/(n+b)]

1/(x^2+x-2)+1/(x^2+7x+10)=2
1/[(x+2)(x-1)]+1/[(x+5)(x+2)]=2
1/(x-1)+1/(x+5)=2(x+2)
2(x+2)/[(x-1)(x+5)=2(x+2)
当x=-2时 分母为0，无意义，即x+2≠0
则(x-1)(x+5)=1
x^2+4x-6=0
(x+2)=10
x=-2±√10

(1/x^2+x-2)+(1/x^2+7x+10)=2求解，过程

应该是 1/(x^2+x-2)+1/(x^2+7x+10)=2
==>1/((X+2)(X-1))+1/((X+2)(X+5))=2
==>(X+2)(X+5)+(X+2)(X-1)=2(X+2)(X-1)(X+2)(X+5)
==>X^2+7X+10+X^2+X-2=2(X+2)(X-1)(X+2)(X+5)
==>2(X^2+4X+4)=2(X+2)(X+2)=2(X+2)(X-1)(X+2)(X+5)
==>1=(X-1)(X+5)=X^2-4X-5 ==>X^2-4X+4-9=1
==>(X-2)^2=10 ==>X=+/-(根下10)+2

1/(x^2+x-2)-1/(x^2+7x+10)=2的解答过程

x^2+x-2 = ( x - 1)(2 + x)
x^2+7x+10 = (2 + x) (5 + x)
1/(x^2+x-2)-1/(x^2+7x+10) = 2
(5 + x) - ( x - 1) = 2( x - 1)((2 + x) (5 + x)
6 = 2( x - 1)((2 + x) (5 + x)
3 = ( x - 1)((2 + x) (5 + x)
x = -4.81691, x = -2.33761, x = 1.15452

解方程1/(x^2+3x+2)+1/(x^2+5x+6)+1/(x^2+7x+12)-1/(x+4)=0

原方程可化为：
1/[(x+1)(x+2)] + 1/[(x+2)(x+3)] +1/[(x+3)(x+4)] - 1/(x+4)=0
裂项得：
1/(x+1) - 1/(x+2) + 1/(x+2) - 1/(x+3) + 1/(x+3) - 1/(x+4) - 1/(x+4)=0
即：1/(x+1) - 2/(x+4)=0
1/(x+1) = 2/(x+4)
x+4=2x+2
解得：x=2
经检验，原方程的解为：x=2

解方程 (7x-2/x^2-1)-7/x+1=1/x+1

两边乘(x+1)(x-1)
7x-2-7(x-1)=x-1
7x-2-7x+7=x-1
5=x-1
x=6
经检验，x=6是方程的解

x-2/7x=1/14 解方程

x-2/7x=1/14
5/7x=1/14
x=1/14÷5/7
x=1/10

x-2/7x=1/28解方程

这个问题有歧义
1.（X-2）/7X=1/28的话
答案：（X-2）x28=7X
28X-56=7X
21X=56
X=3/8
2.X-2/7X=1/28
5/7X=1/28
X=1/20

解方程:X-2/7X=1/14

X-2/7X=1/14
5x/7=1/14
x=1/14×7/5=1/10
x=1/10