# abstract algebra – Prove that ρ is irreducible when \$Mρ(x)=ρ(x)M\$

Be ρ: G $$rightarrow$$ GL(n;$$mathbb{C}$$) a representation of the finite group G. Prove that ρ is irreducible exactly when each matrix M ∈ Mat(n;$$mathbb{C}$$) with $$Mρ(x)=ρ(x)M$$, for each $$x ∈ G$$, of the shape $$λE$$ for a scalar of the λ ∈ $$mathbb{C}$$.

Can anyone give me some help?