How many possible solutions are there to a linear equation in one variable?

Depending on the equation there can be three possible cases: 1 - There can be 1 specific solution for the variable: 2x+4 = 3 where x = - 1/2 2 - there can be an infinite amount of solutions: 2x+x-2=3x-3+1 where x=x 3 - there can be no answer: 3+2x-x=5-3x+4x where the solution doesn't exist