How do I isolate $y$ in $y = 4y + 9$? $y = 4y + 9$
How do I isolate y?
Can I do
$y = 4y + 9$ 
$\frac{y}{4y} = 9$ etc
Also some other questions please:


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*$\frac{5x + 1}{3} - 4 = 5 - 7x$


In the above (1), if I want to remove the '3' from the denominator of the LHS, do I multiply everything on the RHS by 3? What about the '-4' on the LHS, do I do anything to that?


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*In the above


$\frac{y}{4y}$
If I want to solve it, do I cross a y out from the top, or from the bottom? Does that make sense ? :\
Thanks in advance..I have an exam tomorrow..

You have the right idea to get $y$ by itself on the left. However, instead of dividing by $4y$, you would subtract $4y$ from both sides. This will give you
$$y - 4y = 9.$$
Now, if you combine the like $y$-terms on the left. What would $y - 4y$ turn into? You can think of this as: $1y - 4y$. 
For your next problem, if you want to multiply both sides by $3$, then you multiply everything by $3$, including the $-4$ on the left-hand side. 
