# [TIB] Re: help!! ti-89

```Hmm.. rref might be helpful, but simult() looks even more useful.
*checks 89 manual.. page 475* It uses a matrix of coefficients to solve a
system of linear equations.

For example, to solve the system:

x + 2y =  1
3x + 4y = -1
(solution is x=-3 and y=2)

You can use simult to solve it:
simult([1,2;3,4],[1;-1])
[ -3 ]
[  2 ]

Solver might work too, but you'd have to make up coefficients
for every equation. It can be a lot of work, especially if you have a lot of
variables. To use the solver for the same problem would require you to do
this:

solve(x+2y=1 and 3x+4y=-1, {x,y})
x=-3 and y=2

Oh, and FYI, I knew about the comment symbol being the copyright,
but explaining it beyond "just replace it with the (c) symbol"
was going off-topic.. saying "for lack of a copyright symbol"
would be far more confusing and less informative than "for lack
of a comment symbol."

If you MUST type copyright here, there is alt-0169 ©. Just be
warned that even © won't copy and paste back into the graphlink's
program editor correctly, and you'd STILL have to change it
before sending it back to the calculator.

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```