solving for y, you want to get the 'y' by itself on either side of the '=' sign. You would start by simplifying by combining the two 'y', and then subtracting the 2 to the other side to have 'y' by itself, and lastly, you would divide both sides by 'y' so that it gives you the exact value of by 'y'
-12=2+5y+2y
-12=2+7y
-14=7y
-2=y
