Question 178949
One key is to simplify any expression that has a minus sign before a grouping symbol. One example is the last part of this expression. Rewrite that so that you make the minus sign a plus and make sure that the negative gets applies to all the terms in the group. For example:

(3x+5)+(2x-9)-(4x+3)

(3x+5)+(2x-9)  + -1*(4x+3)
(3x+5)+(2x-9)  + (-1)*4x+(-1)*3
(3x+5)+(2x-9)  + -4x-3

The other areas in parentheses do not have a factor that needs to be multiplied or a minus sign in front to simplify and so the parentheses can be dropped without changing the meaning of the expression.

3x+5+2x-9 + -4x-3

Then, reorganize to put like terms together:

3x+2x-4x+5-9+-3

Then, combine like terms:

1x-7  or x-7