Diketahui barisan aritmetika 12,8,4,0,-4 nilai U9+U8 adalah
Jawaban Terkonfirmasi
A = 12
b = 8 – 12 = -4
Un = a+(n-1)b
U9 = a+(n-1)b
= 12+(9-1)(-4)
= 12+8(-4)
= -20
U8 = a+(n-1)b
= 12+(8-1)(-4)
= 12+7(-4)
= -16
U9 + U8 = -20 + -16
= -36 <—- Jawaban
Jawaban Terkonfirmasi
A = 12
b = 8-12 = -4
Un = a+(n-1).b
maka,
U9 + U8
= a+8b + a+7b
= a+a+8b+7b
= 2a+15b
= 2.12+15.(-4)
= 21-60
= -39