How do I know if (8 λ - A) is invertible?

[nicholaskong100]

How do I know if (8 λ - A) is invertible?

I know if the determinant is not zero, it is invertible. But how do I create a matrix out of (8 λ - A)?

 

[blamocur]

Is [imath]\lambda[/imath] a scalar? If it is then maybe the correct expression is [imath]8\lambda I - A[/imath], where [imath]I[/imath] is the identity matrix?

 

[Steven G]

I 2nd 8λI−A