Help with TI-84 Plus Calculator?

Question

Can anyone tell me if it's possible to solve this equation on this calculator?

3a + 3b + c = - 1

a - 3b + 2c = - 5

8a - 2b + 3c = - 22

Thanks a bunch!

Answer 1

Yes you can.

You must set up a 3 x 4 Matrix using the cooefficents and the answers.

Go to Matrix then arrow over to Edit.  Set the dimensions 3 x 4 then enter the numbers.  It should look like this when you are done.

[ 3    3   1   -1

  1   -3   2   -5

  8  -2    3   -22]

After you enter the matrix, quit out of that screen the go to Matrix then arrow over to calculate then go down to rref.  (it is down a little ways)

Hit enter and the screen will show "rref("  now press matrix and hit enter on the matrix that you just typed in.

This should do it for you.

Hope this helps,

Rousey

Answer 2

Hi,

Yes you can solve it easily using matrices.

Go under MATRIX, EDIT, and make a 3 x 4 matrix. Enter this data:

[3...3...1..-1]

[1..-3...2..-5]

[8..-2...3.-22]

Go under MATRIX, CALC, and pick the command rref(. Type the matrix name. If it's A, your screen will say rref([A]). Press ENTER and you will get a matrix like this:

[1...0...0..-1]

[0...1...0..-5]

[0...0...1..-2]

These are NOT the correct answers, but if this was the answer, a = -1, b = -5, and c = -2.

I hope that helps!! :-)