[3 -6 -3] [x]

[ x 2 1] -6 -2 3 -1

-3 -2 0 2

to clarify, the [ x 2 1] is a 1*3.......the A matrix is 3*3....and what i think is b, the x -1 2 is 3*1.

x = ??

the format got jumbled

[x 2 1] [3 -6 -3] [x]
-6 -2 3 -1
-3 2 0 2

still garbled. Try

A =
[...]
[...]
[...]

B =
[...]
[...]
[...]

and do you want X such that AX=B?
If so, then X = A-1B