2/3y+4=12

Answer 1

could you mean:
(2/3)y + 4 = 12
or
2/(3y) + 4 = 12
or
2/(3y+4) = 12
or
2/[3(y+4)] = 12
?
without parentheses I do not have any idea.

Answer 2

however, given the usual sloppiness online, I suspect we have

2/3 y + 4 = 12
2/3 y = 8
y = 3/2 * 8
y = 12