Algebra question . how to solve this

In a caertain fraction, the denominator is 5 less than the numerator. If 5 is added to both the numerator and the denominator, the resulting fraction is equivalent to 5/4. Find the original fraction.

let x=numerator
x-5 = denominator

..
x+5/(x-5+5)=5/4
x+5/x=5/4
5x=4x+20
x=20
original fraction=20/15

x -5 is the denominator
x is the numerator

x/(x-5) original fraction

if (x + 5) / (x - 5 + 5) = 5/ 4

(x + 5) / x = 5/ 4

x = 20
============
substituing at the original fraction
x/ (x-5)

= 20/ (20 - 15)

= 20/15

(d + 5) /d + 1 = 5/4
(d + 5) /d = 1/4
d + 5 = d/4
d - d/4 = -5
3d/4 = -5
d = -5 * 4/3 = -20/3
--> numerator = -20/3 + 5 = (-20 + 15) /3 = -5/3

20/15 i think don't listen to me