Question

pake cara......................

Answer 1

A = -6
n = 9
Un = U9 = 18

Un= a + (n-1) b
U9 = -6 + 8b
18 = -6 + 8b
8b = 24
b = 3

pola barisannya adalah
-6, -3, 0, 3, 6, 9, 12, 15, 18
-6, a , b , c , d , e , f , g ,18

a + d + g
= -3 + 6 + 15
= 18



semoga membantu :))