Texas Instruments TI-89 Titanium Manual page 10

Like the solve function, you can use the matrix function to solve
for a system of equations. For example:
•
Step 1 Press 2
•
Step 2 Enter the coefficients as a matrix and the results as a
constant column matrix as so: simult([3,-5;-2,5],[4;6])
•
Step 3 Press enter. The value for x on top and y on bottom.
Using the same equations, you can solve for x and y using the rref
function.
•
Step 1 Press 2
•
Step 2 Enter an augmented matrix, this contains the variables x,
y, and c where c is the constant. It should look like this: rref([3,-
5,4;-2,5,6])
•
Step 3 Press enter; x is on top, y is on bottom.
3x-5y=4 and -2x+5y=6
nd
5(MATH), 4(Matrix), and then 5(simult).
nd
5(MATH), 4(Matrix), and then 4(rref).