BrianDaMan
New member
- Joined
- May 29, 2021
- Messages
- 1
The question asks me to prove that the second last term in the expansion of (a+b)^n is n/5(n-5) x b^n. The answer says like the photo but i don’t understand that they got (n under 1)a^1b^(n-1). Isn’t it (n under n - 1) if it’s the second last term? Am i getting wrong? Or is the answer wrong?
thanks
thanks