Mohon di jawab soal ini a. 1-2+3-4+5-6+7-8+......-100 b. -100-99-98-......-2-1-0+1+2+....+48+49+50

a•

(1 - 2) + (3 - 4) + ... + (99 - 100) ---> n = 100
= (-1) × 100/2
= -50

b•

-100 - 99 - ... - 50 - 49 ... - 0 + 1 + ... + 49 + 50
= -100 - 99 - 98 - ... - 51 + 0
= -(100 + 99 + 98 + ... + 51) ---> n = 50
= -((100 + 51) + (99 + 52) + ... + (76 + 75))
= -(151 × 50/2)
= -(151 × 25)
= -3775