Hey entrepreneurforum.co.uk.

Given you have AX = 2X + C you can get (A-2I)X = C which implies X = (A-2I)^(-1)*C.

Try calculating (A-2I)^(-1) and see what you get for that.

Note that you can't do what you did (divide by a matrix): you can only pre-multiply or post-multiply and in this particular instance, you need to post multiply since Y^(-1)*Y = I.