diketahui barisan aritmatika . 8,11,14,... . 3, -2, -7,... . 51, 44,37,.. a. hitung suku ke 10 dan 30 b. jumlah suku ke 25

. a. -U10= 8 + (10-1)3
= 8 + 9.3
= 8 + 27
= 35
-U30= 8 + (30-1)3
= 8 + 29.3
= 8 + 87
= 95
b. U25 = 1/2 25(2(8)+ (25-1)3)
= 1/2 25 (16 + 24.3)
= 1/2 25 (16 + 72)
= 1/2 25.88
= 25.44
= 1100
. a. -U10 = 3+ (10-1)-5
= 3 + 9.(-5)
= 3+ (-45)
= -42
-U30= 3 + (30-1)-5
= 3+ 29.(-5)
= 3 +(- 145)
= -142
b. U25 = 1/2 25(2(3)+ (25-1)-5)
= 1/2 25 (6 + 24.(-5))
= 1/2 25 (6 + (-120))
= 1/2 25.(-114)
= 25.(-57)
= 1425

. a. -U10= 51 + (10-1)-7
= 51+ 9.(-7)
= 51 + (-63)
= -12
-U30= 51 + (30-1)-7
= 51 + 29.(-7)
= 51+ (-203)
= -152
b. U25 = 1/2 25(2(51)+ (25-1)-7)
= 1/2 25 (102 + 24.(-7))
= 1/2 25 (102 +168 )
= 1/2 25.270
= 25.135
= 3375
arti (.) adalah kali
maaf kalo salah :)