Question 907468
What is the justification for this: 
=(x)+(x)                                                                          =x+x                                                                              =x
?


Starting with the given:
4×6=x+(x+x)


Work within PARENTHESES first.
(x+x) is handled as combining like-terms of x.  HOW MANY x?


The entire right-side member has only some terms of x.  Still you combine like-terms of x.
x+x+x, the parentheses here not serving any other needed purpose.  HOW MANY x?
The entire right-side member is 3x.