Discrete math. Need help with BOTH questions please!!!

5. Negate the following statements. 5 points cach (a) The function f(r) has a constant derivative and it is linear. (b) If n is even, then is an integer. (c) The number z is even or the number y is evern 6. Prove the following statements using direct proof.10 points cach (Remember this course is about learning how to read/write formal proofs! Use formal definitions in your proofs all the time including the formal definitions of odd and even numbers! "Odd times odd is odd", "odd-+odd-even" type of arguments are not part of our formal proofs!) (a) Let a be an odd integer. Use formal definition of odd integers to prove that a2 +2a+1 is even Note that following is NOT a proof of this statement: Let a 3, then 32+2(3) +1-9+6+1 16 is even. (b) Suppose a, b,ce Z. Prove that if a2lb and bc, then a lc. (c) Prove by using the cases that if r E R, then 31 -x> 2