Three equations in a table
Before typing, write the three equations as a table: one row for each equation. $x+y-z=9$: 1, 1, -1, and 9. $6x+6y-z=17$: 6, 6, -1, and 17. $14x-7y+2z=42$: 14, -7, 2, and 42. The numbers in front of , , and come first, then the number after the equals sign. The calculator asks for them in exactly this order, row by row.