Question

How do I solve a system by using a matrix?

The specific system I'm trying to solve is:
2x - 5y = 4
3x - 6y = 9

Answer 1

do you see how this applies?

Answer 2

Is that how I would multiply them?

Answer 3

Yes I see how it applies

Answer 4

ok
multiply every number in the top ROW by -3/2 and then add each of those numbers to the number underthem

Answer 5

you will see why I choose these numbers when we are done

Answer 6

Wait.. so 2 * -3/2 and -5 * -3/2... which is -3 and 7.5, and then I add them to 3 and -6? 0 and 1.5?

Answer 7

there is actually quite allot to this, and you might want to read about it. Unless you just need to do it once...

Answer 8

http://www.gregthatcher.com/Mathematics/GaussJordan.aspx

Answer 9

try to understand that, its going to be hard for me to walk you through it.

Answer 10

I really only need to do it once lol, it's on a final and my last day of school is in a couple of days.

Answer 11

well that link will show you the exact steps for this problem

Answer 12

okay, thanks! (:

Answer 13

unless dpalnc has a better way of explaining it. There are many rules to what you can do ...and what changes what ...

Answer 14

hmm... isn't that process gaussian elimation???
the question said to use a matrix so just find the inverse of that coefficient matrix and multiply it by the [4, 9]

Answer 15

if hes asking how to row reduce im sure all that iis Chinese to him.

Answer 16

mandarin?

Answer 17

:)

Answer 18

haha...

Answer 19

I'm so confused now :c

Answer 20

can you just use substitution, or do you need to use a matrix?

Answer 21

@TammisaurusRex , forget what i said..

Answer 22

http://www.khanacademy.org/math/linear-algebra/vectors_and_spaces/matrices_elimination/v/matrices--reduced-row-echelon-form-1

this would be a good place to go