This problem doesn't make sense to me. Here it is: Let P(x,y) denote the sentence 2x +y = 1 What is the truth value of ∃x∃xP(x,y) where the domain of x, y is the set of all integers. Doesn't one of the variables need to be a y in ∃x∃xP(x,y)? In other words shouldn't the proposition be ∃x∃yP(x,y) or something similar? Could this simply be a typo? Thanks for any suggestions.