Thread: Binomial Theorem

I understand Binomial Theorem, but this was an extension question and I can't find the answer.

In the expansion of (1+bx)^n , the first three terms are 1-3x+(15/4)x^2. Find b and n.

Could someone please help me? Thanks.

.

So the first three terms are: .

Take it from there...

Write out the first three terms of the expansion and compare it to 1-3x+15x^2/4.