Multiplicity of solutions for critical singular problems

In this work we deal with the class of critical singular quasilinear elliptic problems in RNRN of the form equation(P)−div(|x|−ap|∇u|p−2∇u)=α|x|−bq|u|q−2u+β|x|−drk|u|r−2ux∈RN, where 1