Please answer this discrete mathematics questions.

3. (18 points) Using induction to prove the following equality. Write in detail for four steps below. 2 . 3 + 3 . 4+ ... + (n- 1) .n=(1- 2)(n2 +2n+3) 3 for all integers n 2 3 Proof: Step1: Define the property P(n). Step 2: Basis step. Step 3: Inductive step. Step 4: Conclusion