X represents an unknown number. When 0 times x, it means that 0 times a certain number, which can be any number (of course, it can also mean a formula), and then 0 times x means that 0 times any number should be equal to 0. If it is equal to non-0, there is no solution. You say 2X-2X=(2-2)X=0X=8, that's it, the equation has no solution. So the key to the problem is to remember that 0 times any number is 0.