20=5x-13+6x
We move all terms to the left:
20-(5x-13+6x)=0
We add all the numbers together, and all the variables
-(11x-13)+20=0
We get rid of parentheses
-11x+13+20=0
We add all the numbers together, and all the variables
-11x+33=0
We move all terms containing x to the left, all other terms to the right
-11x=-33
x=-33/-11
x= 3