Question

Tlong bantu jawab yang no 7.. Thanks:)

Answer 1

Verified answer

Bab Pola Bilangan
Matematika SMP Kelas VII

a] 2 + 4 + 6 + ... + 98 + 100 = 
2 + 100 = 102
4 + 98 = 102
6 + 96 = 102
8 + 94 = 102
10 + 92 = 102
------------------------- +
                510

12 sampai 90 = 510
22 sampai 80 = 510
32 sampai  70 = 510
42 sampai 60 = 510

5 x 510 = 2.550

b] -1 + 2 - 3 + 4 - .... + 100 = ?
**hanya berlaku pada bilangan asli berurutan
jumlah = bilangan terakhir / 2
             = 100/2
            = 50

c] -100 - 99 - 98 + ..... + 98 + 99 = ?
-99 + 99 = 0
-98 + 98 = 0
.
.
tersisa = -100
maka, -100 - 99 - 98 + 98 + 99 = - 100

Answer 2

Verified answer

A•
2 + 4 + ... + 98 + 100 ada 50 suku
= (2 + 98) + (4 + 96) + ... + (48 + 52) + 50 + 100
= (100 × 24) + 50 + 100
= 2550

B•
(-1 + 2) + (-3 + 4) + ... + (-99 + 100) ada 100 suku
= (1) + (1) + ... + (1) + (1)
= (1) × 100/2
= 50

C•
-100 - 99 - 98 - ... - 1 + 0 + 1 + 2 + ... + 98 + 99

= -100 + (-99 + 99) + (-98 + 98) + ... + 0
= -100 + 0 + .. + 0
= -100