Find the coefficient of x^7 for (x-3)^11
Use the binomial theorem to expand (2y-3x)^5
Prove that (n over r)= (n over n-r) for all integers where n is greater than or equal to r and r is greater than or equal to zero
Prove that (n over n-2) + ( n+1 over n-1)= n^2 for all integers n is greater than or equal to 2.