Since 7y and 5y has the same variable, add them together.
7y + 5y = 12y
We get 12y, so y has to multiply 12 to get 16. I divided 16 by 12, which got me 1.3333333.
16 divide by 12 = 1.33333333
y = 1.33333333 ( 3 keeps going on )