What is 4th term of the Binomial expansion of (10 + 10)10 ?

Answer 1

(a+x)^10 maybe ?
= a^10 + 10a^9 x^1 + 10*9/2 (a^8 x^2 )
+ [10(9)(8) /(3*2)] a^7 x^3 +..............
which fourth term is
120 a^7 x^3