(x+12)+(4x-16)=6x-13
x+12+4x-16=6x-13
x+4x+12-16=6x-13
5x+12-16=6x-13 ​When there is a x and no number do you assume it is a 1?
5x-4=6x-13 ​Why did the + disappear? Was it for the (-4)
5x-4+4=6x-13+4 How do you know the 4 is supposed to be added and not subtract? ​
5x=6x-9 ​ ​If its 13+4 why was the 4 subtracted?
5x-6x=6x-9-6x ​Why was the 6 subtracted and not the 9? How do you know which
one it is supposed to be?
-x=-9 Why did the -6x effect the 6x and not the 9?
-x/-1=-9/-1 ​How do you know you are supposed to divide with -1? Not another number? and not a positive?
x=9