Question

Tolong d bantu bgt secepatnya pake cara dgn rumus ​mtk kls 8

Answer 1

Jawaban:

B. 781

Penjelasan dengan langkah-langkah:

[Cari beda barusan nya]

U8 = a + 7b = 25

U5 = a + 4b = 16

______________ -

3b = 9

b = 3

[Cari suku pertama nya]

a + 4b = 16

a + 4(3) = 16

a + 12 = 16

a = 4

[Cari nilai dari jumlah 22 suku pertama]

Sn = n/2 × [2a + (n - 1) × b]

S22 = 22/2 × [2(4) + (22 - 1) × 3]

S22 = 11 × (8 + 21 × 3)

S22 = 11 × (8 + 63)

S22 = 11 × 71

S22 = 781