4(8-y)=2y+16
I first multiply thing out on the left
32 - 4y = 2y + 16
With an equation, you can do any math operation on one side if you do the same thing on the other side. It is like a scale that stays balanced as long as you add the amount of weight on both sides.
I'm going to add 4y to both sides
32 - 4y + 4y = 2y + 16 + 4y
You can now combine the y's to simplify
32 = 6y + 16
Subtract 16 from both sides
32 - 16 = 6y + 16 -16
16 = 6y
Divide both sides by 6
16/6 = 6y/6
16/6 = y
or
y = 16/6
this can be simplified since 6 goes into 16 two times with a remainder of of 4/6 or 2/3
y = 2 2/3
in decimal it is about ~ 2.67
It is always a good idea to check your results so
4(8-16/6) = 2(16/6) + 16
Doing the math shows they are both equal, which validates the answer.
After a while you can do these much faster. I can even give you answer without writing anything down in my head, but best to do it all in small steps when you are a beginner. Over time you will get better at it.