A good answer might be:

If ax = b, then (a-1)ax = (a-1)b, or x = (a-1)b (except when a is zero).


Solve for p

The value (a-1) is the inverse of a, and all non-zero real numbers have an inverse. It would be nice to have a similar idea for square matrices.

Say that

Ap = q

for column vectors p and q and n×n matrix A .

If all know are A and q, is it possible to figure out what p is? For example, say that you know that


1   2
0   1
p =

5
2

Try to figure out p from the following. Keep changing the elements of p until the result is q.

A p = q

QUESTION 9:

Did you figure it out?