Question

Solution to Matrix Equation
[9 4] X=[-9 -6]
[2 1] [-1 -8]

Don't understand what x represents.

Answer 1

X represent a matrix that is a solution to the problem

Answer 2

given:

AX = B

a common method of a solution is to augment the system

[A|B] to {I|X}

Answer 3

in other words:

make a new matrix by ... what a good word ... joining? A and B, and row reducing A into the identity matrix, and B becomes X

Answer 4

or if you can take an inverse:

AX = B

A'AX = A'B

X = A'B

Answer 5

rref{{9,4,-9,-6},{2,1,-1,-8}}

http://www.wolframalpha.com/input/?i=rref%7B%7B9%2C4%2C-9%2C-6%7D%2C%7B2%2C1%2C-1%2C-8%7D%7D

notice that the row reduction of A joined to B

the first 1 cols are the identity matrix, and the last 2 columns are X

Answer 6

Oh thanks! You're always saving me, and your explanations are great, helped me a lot, I wasn't familiar with transforming a matrix to a row reduce form. ^^