kak tolong yha yg no. 7 full. a-b-c

Materi : Pola Bilangan

Pembahasan :
Un = 100
2n = 100
n = 50

2 + 4 + 6 + ... + 2n = n(n + 1)
2 + 4 + 6 + ... + 100 = 50(50 + 1)
2 + 4 + 6 + ... + 100 = 50(51)
2 + 4 + 6 + ... + 100 = 2550

————————————————
-1 + 2 - 3 + 4 - ... + 100
= (-1 + 2) + (-3 + 4) + ... + (-99 + 100)
= 1 + 1 + ... + 1
= (100/2)
= 50

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-100 - 99 - ... + 99
= 200/2(-100 + 9)
= 100(-1)
= -100