The TI89 simult function allows to solve a system of equations simultaneously.
Lets solve the following System of Equations using the TI-89s simult command:
1x+2y=3
3x+4y=7
We can see that x=1 and y=1 solves this system. Let the TI89 do it for us.
Press CATALOG and press S to jump to simult( , press ENTER.

Next, type in our system of equation using a 2×2 and a 2×1 matrix as shown below.
You may copy this to your TI89: simult( [1,2;3,4],[3;7])
Press ENTER to get the solution as a matrix shown below,

FYI, using the simult function yields the same answer as using the solve function by typing in the two equations using x and y variables.


In conclusion, the simult function of the TI89 calculator allows solving a system of equations without typing in the variables involved but rather using matrix notation.
Watch the Ti89’s simult() function in action below: