Week 4, Eigenvalues and eigenvectors, Finding eigenvectors

Where does this equation come from, in the previous explanation, there is no number (2 and 3), it’s just the matrix bellow
Screenshot 2023-09-22 104241
and
image

@Asyafa_Ditra_Al_Haun, were you able to find an answer to this question?

I did it after do some research, actually it just come from the previous equation explained in that video