Question

U2 + U8 = 56 dan U7 + U9 = 86 maka suku ke 2 adalah?

Answer 1

U2 + U8 = 56
a +b + a+7b = 56
2a + 8b = 56...(1)

U7 + U9 = 86
a+6b + a+8b = 86
2a + 14b = 86 ...(2)

2a + 8b = 56
2a + 14b= 86
___________ _
-6b = -30
b = 5

2a + 8(5) =56
2a+ 40 = 56
2a = 16
a = 8

U2 = a + b = 8+ 5 = 13