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Answer:

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

A = parens
1   2
0   1
parens , and that q = parens
5
2
parens

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

A p = result (should be q)
parens parens parens parens parens parens

You can only change p in the above. Click on the = button to see the result with each change you make. Keep changing p, searching for the one that produces the result you want (i.e., q).


QUESTION 9:

Did you figure it out?