+25 (a) Simplify (nk)(nk−1)
(b) In the expansion of (1+x)n there exist three consecutive coefficients a,b,c that satisfy a:b:c=1:7:35. Find the positive integer n.
Thank youuuu!
+2096 a) Note that a combination is n!/(r)!*(n-4)!
We can write the equation in this form, and then simplify.
Hope this helped!
