This calculator requires input to be in the form:
                     aX +  bY =  c

EXAMPLE:  If you have the equations:
                         2X   + 3Y  =  12
                         3X   -  4Y  =    1
then you would enter:
       Eqtn 1:      2          3       12
       Eqtn 2:      3        - 4         1 

Click E N T E R and the answers are X=3    Y=2