200k views
0 votes
Find the 13th term of the binomial expansion of: (2x-4)^21 Please help :(

User GJZ
by
8.2k points

1 Answer

4 votes

T_r={n \choose r-1}a^(n-r+1)b^(r-1)\\ T_(13)={21 \choose 13-1}(2x)^(21-13+1)(-4)^(13-1)\\ T_(13)={21 \choose 12}(2x)^9(-4)^(12)\\ T_(13)=(21!)/(12!9!)\cdot512x^9\cdot16777216\\ T_(13)=293930\cdot8589934592x^9\\ T_(13)=2524839474626560x^9
User Illusionx
by
8.3k points

No related questions found