1. ## Matrix problem 2

Im having another matrix problem...

I cant find the solution to this one, every time I try it seems to go wrong. The answer i get is x=15 y=11 and z=30, and that cant be correct in any way

How do I find x,y, and z? And is there really a solution to this one? Thanks!

2. Gauss, Gauss-Jordan.

3. Originally Posted by Krizalid
Gauss, Gauss-Jordan.

Easier to just do it with a matrix I think, Gaussian equations are an unnecessary waste of time IMO.

(-5 2 1)( X) = (-5)
(1 -4 1)( Y) (1)
(1 1 -1)(Z) (2)

Sorry for the messy brackets there, not sure how to setup a matrix on the forums here.

Anyways those are your original values input into a matrix, now what you have to do is find the inverse of(Using a calculator):

(-5 2 1)
(1 -4 1)
(1 1 -1)

Which will give you the identity matrix:

(1 0 0)
(0 1 0)
(0 0 1)

Therefore on the left side you will be left with:

(1 0 0)(X)
(0 1 0)(Y)
(0 0 1)(Z)

Now what you have to do is multiply the inverse for(Obviously your 3x3 matrix has to be in front of the other):

(-5 2 1)
(1 -4 1)
(1 1 -1)

By:

(-5)
(1)
(2)