Here is the equation given:

In the equation, you're looking for y. That means you need to move anything with the variable y to the other side.
In this equation, you have 12-4y. To move 12 to the other side, you will need to subtract 12 on both sides. This is because when a variable or integer is moved, the sign changes. The 12 was originally positive, but when moving it, it will become -12, which is why it was subtracted.

Remember you're looking for y alone. y is currently -4y. To remove the -4 that is being multiplied by y, you will need to do the opposite of it, which is divide by -4. Divide both sides by -4:

When a negative number is multiplied by another negative number, the sign becomes positive. On the left side, you have -6x-12, which is being divided by -4. When you divide,
becomes
.

cans till be simplified. The greatest common factor of 6 and 4 is 2, so divide the fraction by 2.

That means 
The answer you are looking is
.