Question 632016
(a + b)^10
eighth term:
10C7 a^(10-7)b^7
10C7 a^3b^7
10!/7!(10-7)! a^3b^7
(8*9*10)/3! a^3b^7
(8*9*10)/(3*2*1) a^3b^7
(8*9*10)/(1*2*3) a^3b^7
(4*9*10)/(1*3) a^3b^7
(4*3*10) a^3b^7
120a^3b^7