Barisan aritmatika memiliki U7= 27 dan U11=43 nilai u9 adalh

U7 = a+(7-1)b = 27
u11 = a+(11-1)b = 43

u7=a+6b=27
u11=a+10b=43
-------------------- — (metode eliminasi)
-4b = -16
b = 4

a = a +6(4)= 27
a= a+24= 27
a= 27-24
a= 3

u9 = 3 + (9-1)4
u9 = 3 + 32
u9 = 35

maaf jika salah