Answer
It has infinitely many solutions.
Work Step by Step
In order to find out if the equation has infinitely many solutions or no solution (the null set), we multiply each of the three equations by a constant so that when the equations are added, all of the variables cancel. If the resulting expression is true, the solution set is all real solutions, while if the resulting statement is false, there is no solution. Thus, we multiply the first equation by -1, the second equation by -1, and the bottom equation by 1 to obtain:
$0 = -1 - 3 +4 \\ 0 = 0$
There are infinitely many solutions.
