Core 1 maths help? Thank you for anyone who answers this. Find the coefficient of x^6 in the expansion of (1+3x)^12 By my reckoning that is the Pascal's Triangle number x 3x^6 x 1 ^6 The Pascal's Triangle number is: (12 x 11 x 10 x 9 x 8 x 7) / (1 x 2 x 3 x 4 x 5 x 6) = 308 so the answer is 924x^6 ? Also, to find the x^7 coefficient in the expansion of (1-2x)^15, is it just the same, only with a negative sign? Thanks

Yeah, but we've been taught a much simpler formula for it. Instead of n!/r! (n-r!) You just do one simple fraction, but with lots of numbers it can get complicated as above!