Kulay, there is no such thing as a "step by step answer" here. You seem to want a "step by step solution."
I must assume that by 4/5 you actually meant (4/5) and that by 2/3 you meant (2/3). Then your equation becomes:
(4/5)w - 12 = (2/3)w.
The LCD here is 5*3, or 15, so mult. every term by 15:
12w - 180 = 10w.
Add 180 to both sides, obtaining 12 w - 180 + 180 = 10w + 180.
Then 12w = 10w + 180. Simplifying, 2w = 180. What is w?