Non-standard angular momentum principle if a is a generally

Question

Non-standard angular momentum principle If A is a generally moving point of space and LA is the angular momentum of a system S about A in its motion relative to A, show that the angular momentum principle for S about A takes the non-standard form

(dL_A/dt) = K_A - M(R-a) X (d²a/dt²)

[Begin by expanding the expression for LA.] When does this formula reduce to the standard form?