Solution 24770: Solving a System of Linear Equations on the TI-Nspire™ Family.
How do I simultaneously solve a system of linear equations on the TI-Nspire family?
Simultaneously solving a system of linear equations on the TI-Nspire family products can be done using the simult( command. The following example will solve x and y for the equations:
x + 2y = 1
3x + 4y = -1
1) Press [home] [A] or add a Calculator app. This is the first option on the available icons at the bottom.
2) Press [catalog] [S].
3) Scroll to simult( and press [enter].
4) Press [template]. This is the key located to the right of .
5) Scroll to the second row, sixth column and press [enter].
6) Press [del]  [tab] [del]  [enter].
7) Press  [tab]  [tab]  [tab]  [tab].
8) Press [,] [template].
9) Scroll to the second row, fifth column and press [enter].
10) Press  [tab] [(-)]  [enter].
TI-Nspire CAS family:
In addition to using the simult( command, the TI-Nspire CAS family can also use the solve( command and the simultaneous equation template to solve simultaneous equations:
1) Press [menu]  .
2a) If you have Touchpad Press [template key]
2b) If you have ClickPad Press [ctrl] [multiplication sign] to access the template menu.
3) Scroll to the first row, ninth column.
4) Press [X] [+]  [Y] [=]  [tab].
5) Press  [X] [+]  [Y] [=] [(-)] .
6) Press [tab] [,] [X] [,] [Y] [enter].
Please see the TI-Nspire CX, TI-Nspire CX CAS, TI-Nspire and TI-Nspire CAS guidebooks for additional information.