Linear Transformations and eigenvectors, need assistance

have L be the linear transformation on R2 that reflects each point P across the line y = ax (a > 0).

 

I need to show that v₁ = [a, a²] and v₂ = [-1, 1/a] are hte eigenvectors of L

 

note: v1 and v2 are vertical 2x1 matrices and L is 2x2