Verified Answer :

15x - 8 = 14x + 13    |add 8 to both sides

15x = 14x + 21      |subtract 14x from both sides

x = 21

\(15x - 8 =14x + 13\) 

\(15x=14x+13+8\) 

\(15x=14x+21\)

\(15x-14x=21\) 

\(x=21\)