SOLUTION: Please help me solve this problem {{{abs(f+3)=2f+4}}}

There are two cases to consider: 

Case 1:   where 

Case 2:   where 

Let's do case 1 first:

 where 

Then to get rid of the absolute value bars, we can just drop
them because the absolute value of any positive number
is just that positive number and the absolute value of 0
is also just that number, 0.  So

  becomes



Solve that and get 

So that is one solution, for when we check it,







------

Now let's do case 2:

 where 

Here  is a negative number. Therefore to get 
rid of the absolute value bars, we can make the negative 
number  positive by multiplying it by -1.  So

  becomes



Solve that and get 

However that is not a solution, for when we check it,






=

So there is just one solution, 

Edwin