(+-) means the plus sign over the minus sign. In other words, both positive and negative.

a) Suppose X' = AX where A is a 4x4 matrix whose eigenvalues are (+-)i*sqrt(2) and (+-)i*sqrt(3). Describe this flow.

b) Suppose X' = AX where A is a 4x4 matrix whose eigenvalues are (+-)i and -1(+-)i. Describe this flow.

c) Suppose X' = AX where A is a 4x4 matrix whose eigenvalues are (+-)i and (+-)1. Describe this flow.

I have no idea where to even start with these

And Mods, I don't know why I got docked for posting my last thread in Differential Equations since the questions came from my Differential Equations class.