So apparently you have ,and in full form, according to what you wrote,

Now, assuming A is invertible, we get , so assuming you did calculate the inverse of A correctly , you

get , and the you only do the matrix product on the left to find out what the vector x (i.e., x_1,x_2,...) is.

Unfortunately, your calculation of is incorrect, as multiplying it by A we do NOT get 0 in the entry 1-2, as we should...so check this and then do as above.

Tonio