Problem with matrices question, finding A^2

The question is this one below:

Let

A =

(1 -3)

2 0

How am I supposed to find A^2?

Also Let

B =

(-6 3 )

8 20

How do I find Matrix X such that 5X-A=B ?

Full explanations would be nice, someone tried to explain it to me briefly but I didn't quite understand it.

Re: Problem with matrices question, finding A^2

Quote:

Originally Posted by

**DaveWolfgang** How am I supposed to find A^2?

Quote:

Originally Posted by

**DaveWolfgang** How do I find Matrix X such that 5X-A=B ?

You know that has to be a 2×2 matrix for the subtraction to be valid. If we let

then

Now equate the corresponding entries.

Re: Problem with matrices question, finding A^2

Quote:

Originally Posted by

**DaveWolfgang** How do I find Matrix X such that 5X-A=B ?

Or just X = (1/5)(B + A).