Respuesta :

first of all you need push the restriction for what x value the denominator result 0 bc. than this fraction will be undefined 
- so x^2 -25 = 0
(x-5)(x+5)=0
x-5=0 =>x=5
and 
x+5=0 =>x=-5
so this mean that x not can being equal +/- 5 

rewrite :
x^2 -25 = (x-5)(x+5)

   2x                       10                 4
------------- = ------------------ - -----------
(x-5)(x+5)       (x-5)(x+5)          x +5

    2x = 10 -4(x-5)
2x = 10 -4x +20

6x = 30

x = 30/6

x = 5 what is restriction for x 

hope helped