1. ## Evaluate (A+1)(A-I)

Hi,

Suppose A+I = $\displaystyle $\begin{pmatrix} 1 & 3 & 4 \\ -1 & 1 & 3 \\ -2 & -3 & 1 \\ \end{pmatrix}$$ evaluate (A+I)(A-I)

Can I assume that A = $\displaystyle $\begin{pmatrix} 0 & 3 & 4 \\ -1 & 0 & 3 \\ -2 & -3 & 0 \\ \end{pmatrix}$$ ?

Therefore, can I evaluate (A+I)(A-I) by multiplying these two matricies?: $\displaystyle $\begin{pmatrix} 1 & 3 & 4 \\ -1 & 1 & 3 \\ -2 & -3 & 1 \\ \end{pmatrix}$$ $\displaystyle $\begin{pmatrix} -1 & 3 & 4 \\ -1 & -1 & 3 \\ -2 & -3 & -1 \\ \end{pmatrix}$$

2. Yes.

3. Originally Posted by TheEmptySet
Yes.
Thanks TheEmptySet!