suatu barisan aritmatika diketahui U4=8,U8=16 suku ke 12 adalah

dik= u4=8
u8=18
dit= u12
jawab=
u4=a+(4-1).b=8
u4=a+(3).b

u8=a+(8-1).b=16
u8=a+(7).b

u8=a+(7).b=16
u4=a+(3).b=8
=4b=8
b=8÷4=2

u4=a+(3).2=8
a+6=8
a=8-6=2

u12=2+(11).2
u12=2+22
u12=24

U4 = a + 3b = 8
U8 = a + 7b = 16
_____________ -
0 + -4b = -8
b = -8 : -4 = 2

a + 3b = 8
a + 3×2 = 8
a + 6 = 8
a = 8 - 6
a = 2

U12 = a+(n - 1)b
= 2 + (12 -1 ) 2
= 2 + 11 × 2
= 2 + 22
= 24
jawabannya 24