I have made an application for all Android phones called Elementary Row Operations. It can be used for finding the solution to a system of equations, for reducing a matrix to reduced row echelon form, and for finding the inverse and determinate of a matrix. One can find the app on the Android market by searching for the app name. Use spaces to distinguish between numbers in a row and a new line to distinguish between rows. Numbers can be entered as decimals or fractions, so 0.75, .75, 3/4, and 1.5/2 are all valid. Here are some sample screen captures demonstrating finding the inverse of a matrix:
