Hello everyone, i have no idea why i can't grasp this simple concept...(adsbygoogle = window.adsbygoogle || []).push({});

i have:

A =

1 4 9

0 1 9

0 0 1

I have to find A^-1, A inverse.

So I found the determinant along row 3,

1*det(B) = 1;

B =

1 4

0 1

det(B) = (1)(1) - (4)(0) = 1;

so i take 1/det * A now wouldn't that just be A itself?

When i submitted the answer

A inverse =

1 4 9

0 1 9

0 0 1

it said,

Entered Answer Preview Result

1 1 correct

4 4 incorrect

9 9 incorrect

0 0 correct

1 1 correct

9 9 incorrect

0 0 correct

0 0 correct

1 1 correct

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# Homework Help: Why can't i figure out inverses! ahh! simple 3X3 matrix

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