Complete the steps of the argument below. For each step, choose a rule of inference or logical equivalence that justifies the step and indicate which statements the rule is applied to. To reference previous statements, write their numbers separated by commas (e.g.: 1 or 1,2 or 1,2,3). 1. 3xU(x) 2. Vx (P(x) U(x)) 3. U (b) for some b, using Existential Instantiation with 1 4. P(b) U(b), using Universal Generalization 5. P(b), using Modus Tollens Basic Rules of Inference table with 3,1 6. P(b) v R(b), using Resolution 7.3x (P(x) v R(x)), using Existential Generalization Note: You can earn partial credit on this problem. with 4,3 with 5,4 V with 5,3