Knowledge Base

Solution 10356: Solving Simultaneous Equations on the TI-85 or TI-86.

How do I solve simultaneous equations on the TI-85 or TI-86?

The example below will demonstrate how to use the SIMULT function to solve simultaneous equations on the TI-85 or TI-86.

Example: Solve the following for x, y and z.

3x + 3y - 4z = -3
-x + 2y + 5z = 18
8x + 4y - 7z = -5

Solution:

1) Press [2nd] [SIMULT]
2) Input 3 (This indicates that there are three equations to solve.)
3) Press [ENTER] 
4) Input the coefficients for the first equation pressing [ENTER] after each value.
5) Press [3] [ENTER] [3] [ENTER] [(-)] [4] [ENTER] [(-)] [3] [ENTER].
6) Repeat the same steps for the next two equations.
7) Press [F5] to display the results.

The given solution will show:

x1=1
x2=2
x3=3

Please see the TI-85 and TI-86 guidebooks for additional information.