This is an equation that needs to be simplified, so its not contradiction or identity. You have to get rid of a variable on one side. You do that by either subtracting 5x from both sides of 1x from both sides. Doing both will end up the same answer. So lets just say that you subtract 1x from each side and you end up with -5=4x+6. Then you add 6 to both sides and you end up with 1=5x. And then divide each side by 5. And then there is your answer.