-100-99-99...........-2-1-0+1+2+........+48+49+50 jawab pakai jalannya besok mau dikumpul

Bab Pola Bilangan
Matematika SMP Kelas VII

-100 - 99 - 98 - ... - 1 + 0 + 1 + ...49 + 50 = ?
-50 + 50 = 0
-49 + 49 = 0
.
.
-1 + 1 = 0

sisa = -100 - 99 - 98 - .. - 51 = ?
-100
-99 - 51 = -150
- 98 - 52 = -150
.
-76 - 74 = - 150
-75
seluruh = (-76 sampai -80) + (-81 sampai -90) + (-91 sampai -99) + (-100) + -75
seluruh = (5 x (-150)) + (10 x (-150)) + (9 x (-150)) - 100 - 75
seluruh= -750 - 1.500 - 1.350 - 175
seluruh = -3.775

-100-99-98.......-2-1-0+1+2+......+48+49+50

(-50-49-48......-2-1-0+1+2+...+48+49+50) = 0

-100-99-98-............-51

a = -100
b = -99 - (-100) = -99 + 100 = 1
n = 100/2 = 50

Sn = 1/2 (n) [2a + (n - 1)b]
S50 = 1/2(50)[2(-100) + (50 - 1)× 1)
S50 = 25[-200 + 49]
S50 = 25 × (-151)
S50 = -3775