You can use GeoGebra to solve systems of equations with multiple unknowns.
GeoGebra Instruction 1
CAS under View in Menu. CAS, pressing Enter to start a new row for each of your equations. Shift key, click the box of the first equation and then click the box with the row number of the last equation. Solve
If you get as the output, the system of equations has no solution. If GeoGebra returns one of the variables as a function , then the system of equations has infinitely many solutions.