Binomial expansion help?Watch
I thought there are two ways of getting x^2, one by just having an x^2 term from the right bracket and multiplying that by 5, and the other is by having a x term and then multiplying that by x.
Either way is not getting me to the correct answer. ive attached my shity working incase ur interested lol.
Also by finding x^2 the first way i mentioned, that gives an k^2, so therefore that itself gives two vlaues of k. So altogether i get like 3 values which is DEFO wrong....
i was sort of close with my initial method i just forgot to add them together which is so annoying:/
If we are given nC2 is 15 is there a way to work out the value of n without trial and error using a calc? using the formula would be really complicated cuz of the factorials right?
Again, do it the long way, and learn the shortcut.