What are the domain restrictions of q2−3q−4q2−7q−8?

Which is the completely factored from of xy^3-x^3y

What is the missing statement in step 4? ? rts ? ? vtu and ? rtu ? ? vts ? rts ? ? rvs and ? rtu ? ? stv ? vrs ? ? vru and ? usr ? ? usv ? vur ? ? vus and ? uvs ? ? sru

The anwser cause i do not understand just plez