Binomal Theorem
posted by Tommy .
1A> What is the coefficient of x^(2r) in the expansion of (1x^2)^n, where n is a positive integer ?
1B> Find the coefficient of (1+x)^7 (1x) ^8
Thanks for your help :)

1A> There is no x^(2r) term. Do you mean the x^2 term coefficient?
1B> Which coefficient do you want? You only ask for one, but there are 15 of them.
This web site will tell you how to use the binomial theorem to get the coefficients of polynomials:
http://www.wtamu.edu/academic/anns/mps/math/mathlab/col_algebra/col_alg_tut54_bi_theor.htm 
in the first part, r is any integer.
in the second part, i wanna find the coefficient of x^7 
actually my teacher didn't teach me anything about binomial theorem. This topic is selfstudied.

We did this in Algebra III, but I can not remember how to do it. What course does this fall under for you, Tommy? Is there a section in your textbook that mentions this, possibly as an extension or application or some such extra bonus material?

It is additional maths.
I learnt the binomial theorem, the (r+1) term theorem, how to expand the binomial expression using the the pascal triangle. 
pls help me with this binomial expansion