Answer :

[tex] 5x - 1 = x + 15 [/tex]
subtract x to both sides
[tex] 4x - 1 = 15 [/tex]
add 1 to both sides
[tex] 4x = 16 [/tex]
divide 4 to both sides
[tex] x = 4[/tex] 
AL2006
-- Add  1  to each side.

-- Then subtract 'x' from each side.

-- Finally, divide each side by  4, and the answer will jump out at you.