Pertanyaan
Diketahui barisan 5,12,21,32,..... Suku ke-20 barisan tersebut adalah.....
a. 480
b. 450
c. 420
d. 400
a. 480
b. 450
c. 420
d. 400
Ditanyakan oleh: USER7476
123 Dilihat
123 Jawaban
Jawaban (123)
maaf ralat ..
a+b+c = 5
3a + b = 7
2a = 2
2a = 2 , a = 1
3a+b = 7
3.1+b = 7 , b = 7-3 = 4
a+b+c = 5
1+4+c = 5 , c = 5-5 = 0
Un= an^2 + bn + C
U20 = 1.20^2 + 4.20
U20 = 400 +80
U20 = 480
a+b+c = 5
3a + b = 7
2a = 2
2a = 2 , a = 1
3a+b = 7
3.1+b = 7 , b = 7-3 = 4
a+b+c = 5
1+4+c = 5 , c = 5-5 = 0
Un= an^2 + bn + C
U20 = 1.20^2 + 4.20
U20 = 400 +80
U20 = 480