Question

Gmbarnya masih kurang jelas? no 12 dan 14

Answer 1

12) 7C3 x 9C2 = 7!/(7-3)!.3! x 9!/(9-2)!.2!
= 7.6.5.4!/4!.3.2.1 x 9.8.7!/7!.2.1
= 35 x 36
= 1260

13)(2x^2 - 1/2y^3)^8
a = 2x^2
b = -1/2 y^3
n = 8
suku ke 5 maka : r = 4
nCr . a^(n - r) . b^r
= 8C4 . (2x^2)^(8 - 4) . (-1/2 y^3)^4
= 8!/(8-4)!.4! . (2x^2)^4 . 1/16 y^12
= 8.7.6.5.4!/4!4.3.2.1 . 16x^8 . 1/16 y^12
= 70x^8 y^12