If you solve an equation and the variable disappears you end up with one of two results:
0 = 0
0 = 8 (or any number other than 0)
When you get one of these equations, ask yourself, "Is this always true, or is this never true?"
In the first case, the answer is "all real numbers." If you had two or more equations, it is also called a "dependent system."
In the second case, the answer is "no solution." If you had two or more equations, it is also called an "inconsistent system."