Question

Let X₁ and X₂ be independent binomial random variables with Xᵢ having parameters (nᵢ, pᵢ), i=1,2. Find
(a) P(X₁X₁ = 0)
(b) P(X₁ + X₂ = 1)
(c) P(X₁ + X₂ = 2)