Check my precalculus homework answers

[r-soy]

Hi

here I put my answer as a picture

Q

[PLAIN]http://up.arab-x.com/Mar10/HnA33086.jpg

A

[PLAIN]http://up.arab-x.com/Mar10/8SE29265.jpg

http://arb-up.com/i/00020/a00rnukl7nt0.jpg

http://arb-up.com/i/00020/88tl6yd7jk3p.jpg

http://arb-up.com/i/00020/2d5d712yhh03.jpg

 

[Mark44]

Hi

here I put my answer as a picture

Q

[PLAIN]http://up.arab-x.com/Mar10/HnA33086.jpg

A

[PLAIN]http://up.arab-x.com/Mar10/8SE29265.jpg

http://arb-up.com/i/00020/a00rnukl7nt0.jpg

http://arb-up.com/i/00020/88tl6yd7jk3p.jpg

http://arb-up.com/i/00020/2d5d712yhh03.jpg

You have obviously made a mistake somewhere, either in the inverse or in your check. When you multiplied A^-1 by A, you should have gotten the identity matrix I, but you didn't. That should be a clue that you've done something wrong.