MAT 243 Written Homework #5 1.6, 1.7, 2.4 Due: September 2 Solve the following problems, showing any necessary work. That means you must include the Rules of Inferences in any proofs which are assigned. 1. Give a proof by Contradiction for each of the following problems. a. [5 points] Prove-1-q (-pv s), assuming the following: (2) pV T (3) -s (A) T (Hint: Prove p^-p.) b. [5 points] Let f: Z-Z be the function given by f(x)-3x -5. Prove that f is NOT onto, using the definition of onto: f:A B is onto iff (Vy B)(Ex E A (f(x)-y)