The others did not see your earliest post.  This is what you posted
that you had done:

Your error was in removing parentheses when there is a minus sign preceding
the parentheses.

You changed  - (x+3) to -x+3 when you should have changed it to -x-3.

BOTH SIGNS are changed when removing the parentheses, not just the first
one.

When an expression in parentheses is preceded by a minus or negative sign,
it is the same as if you were distributing -1 into the parentheses.

So when you see -(x+3), consider it to be 

                -1(x+3)

then distribute like this

               (-1)(x)+(-1)(3)

then

                -x + (-3)

and finally

                -x - 3

Now do the problem again, using -x - 3, not what you had.      

Edwin