tolong bantu soal no 6&7

Kelas 10 Matematika
Bab Barisan dan Deret Bilangan, Serta Nilai Mutlak

6] r = ⁷⁻¹√(U7/U1)
r = ⁶√(192/3)
r = ⁶√64
r = 2

Sn = a . (rⁿ - 1) / (r - 1)

S7 = 3 . (2⁷ - 1)/ (2 - 1)
S7 = 3 . (128 - 1) / 1
S7 = 3 . 127
S7 = 381 cm

7] |x - 5| - 2 = 0
|x - 5| = 2

x - 5 = 2
x = 5 + 2
x = 7

x - 5 = -2
x = 5 - 2
x = 3

HP = { 3, 7 }