Inverse of the matrix $$\left[\begin{matrix} 11& -5\2&-1 \end{matrix}
\right]$$
$$-1\left[\begin{matrix} -1& 2\-5&11 \end{matrix}
\right]$$
=$$\left[\begin{matrix} 1& -2\5&-11 \end{matrix}
\right]$$

Question

Inverse of the matrix $$\left[\begin{matrix} 11& -5\2&-1 \end{matrix}
\right]$$
$$-1\left[\begin{matrix} -1& 2\-5&11 \end{matrix}
\right]$$
=$$\left[\begin{matrix} 1& -2\5&-11 \end{matrix}
\right]$$

anonymous · Answer

I did the matrix wrong...but what did I do wrong?
@Outkast3r09

anonymous · Answer

you aren't supposed to switch the position of the 2 and -5, only the sign.

anonymous · Answer

can you state the rule for me please? so I would change the position of the 11 and -1 but not the 2 and -5?

anonymous · Answer

right.  if the matrix is:

a  b
c  d

you swap a and d, and change the sign of b and c, so you should get:

  d  -b
-c    a

Then you just divide everything by the determinant.

anonymous · Answer

so it's 
1   -5
2   -11
Thanks!