1/3y+1/4=5/12 how can you solve that ?

4/12y + 3/12 = 5/12
4/12y = 5/12 - 3/12
4/12y = 2/12
4y = 2
Y = 2

  example you can find the perimeter by addig all of its respective sides as such: (12+x)+(12+x)+(7+y)+(7+y).  adding like terms will result in   2x+2y+38    if you chose  xy+7x+12y+84, you multiplied the two sides to find the area.  if you chose  x+y+19