Solution 34852: Calculating the Inverse of a Matrix on the TI-84 Plus C Silver Edition Graphing Calculator.
How do I calculate the inverse of a matrix on a TI-84 Plus C Silver Edition graphing calculator?
The example below will show how to calculate the inverse of a square matrix.
For Example: Find the inverse of matrix A
First enter the matrix:
1) Press [2nd] [MATRX] scroll to edit
2) Press 1
3) Input the dimensions of the matrix (2 [ENTER] 2 [ENTER])
4) Input the values for the elements of the matrix pressing [ENTER] after each entry
5) Press [2nd] [QUIT] to return to the home screen
To find the inverse of matrix A
6) Press [2nd] [MATRX]  [x-1] [ENTER]
Please Note: A singular matrix does not have an inverse. A singular matrix by definition is a matrix whose determinant equals zero.
Please see the TI-84 Plus C Silver Edition guidebook for additional information.