solve for y in the formula

x=2y/2y+5

The way you typed it, it would become

x = 2y/2 * y + 5
somehow I don't think you meant that.

If you meant: x = 2y/(2y) + 5, the 2y would cancel and the statement would be false

If you meant:
x = 2y/(2y+5)
cross-multiply ...
2xy + 5x = 2y
2xy - 2y = -5x
y(2x - 2) = -5x
y = -5x/(2x - 2) OR
y = 5x/(2 - 2x), OR
y = 5x/(2(1-x))

Can you see how critical brackets are in this format?