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 Solve the following 
 .
.

 First of all, we can remove the parentheses by multiplying 2 times x and 3:-
 

Now that we removed the parentheses, the rest is a piece of cake, as long as we pay attention to the signs, and here's what I mean by that.
 Subtract x on both sides:-
 

 On simplification, we get
 

 Now we subtract 6 on both sides, which results in
 

And finally,

[Verification]
We can substitute -10 for x and see whether or not we end up with a true statement.

Perform the operation inside the parentheses first:-

On simplification, we get

 Since the left-hand side (L.H.S.) is the same as the right-hand side (R.H.S), our solution (x=-10) is correct.
Good luck.
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