tolong bantu pakek cara,nanti saya like dan follow besok kumpul

3. 2 liter = 7000 KJ
5 liter = ???

2 / 5 = 7000 / a
5 x 7000 = 2 x a
35.000 / 2 = 17.500 KJ


4.
21 = 21 = 21 = 21 = 7 = 1
42 = 21 = 21 = 21 = 7 = 1
72 = 36 = 18 = 9 = 3 = 1
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KPK = 2 x 2 x 2 x 3 x 3 x 7

Faktorisasi prima
2³ x 3² x 7