well there is no need to get confused with such a thing she distributed -2 to x and 4 bcoz there is no way in which you can solve the parenthesis as you dont know the value of x . you have to first simplify and then solve the equation for the value of x. If in place of x you would have had some number, say 7 , then in that case you could have added 7 and 4 as they are like terms and solved the parenthesis first and then multiplied by -2. But since x and 4 are not like terms you cannot solve them together. So the only option you have is to distribute -2 to x and 4. hope you get it now.