Barisan aritmetika memiliki U7=27 dan U11=43,Nilai U9 adalah

U7 = a + 6b = 27
U11 = a + 10b = 43
_______________ –
-4b = -16
b =-16/-4= 4
Subsitusi b =4
a + 6(4) = 27
a + (24) = 27
a = 27 -24
a = 3

U9 = a + 8b = 3 + 8(4) = 3 + 32 = 35