To solve for y, you need to get y by itself on one side of the equation. To do this, you can start by moving all the terms that contain y to the left-hand side of the equation, and all the other terms to the right-hand side.
You can do this by adding 2/5y to both sides of the equation:
1/3x - 2/5y + 2/5y = -4 + 2/5y
This simplifies to:
1/3x = -4 + 2/5y
Then, you can add 4 to both sides of the equation to get:
1/3x + 4 = 2/5y
Finally, you can divide both sides of the equation by 2/5 to solve for y:
(1/3x + 4) * (5/2) = 2/5y * (5/2)
This simplifies to:
(5/6x + 20/2) = y
Which is equal to:
y = 5/6x + 10
So the solution for y is y = 5/6x + 10.