Ok I'll help you through it.
Write down the first few terms of (1+ax)^n
Given that n is a positive integer and that a and b are real constants, find a and bi if :
(1+ax)^n=1-6x+(81/5)x^2+bx^3+……….
Hint: You must solve for n first
A step by step explanation would be greatly appreciated. This question really has me stumped and the teacher's explanation didn't help.