Question 504341
The basic thing you need to remember is that when solving equations, you're following PEMDAS in reverse to isolate the variable.



So normally, you'd use PEMDAS to get 



2*3+5 = 11



But say that the '3' was really an x, so we now have 



2x+5 = 11



Now follow PEMDAS in reverse (ie undo addition/subtraction, then undo multiplication/division, etc) to get



2x+5 - 5 = 11 - 5


2x+0 = 6


2x = 6


x = 6/2


x = 3