TOLONGGGGGGGGG PAKE CARA YA:V

U2 = a + b = 10
U6 = a + 5b = 22

gunakan metode eliminasi.

a + 5b = 22
a + b = 10
——————— -
[tex]4b = 12 \\ b = \frac{12}{4} \\ b = 3 [/tex]

kemudian, gunakan metode substitusi.

a + b = 10
a + 3 = 10
a = 10 - 3
a = 7

sudah diketahui a = 7 dan b = 3 , maka :

Sn = n/2 ( 2a + ( n - 1 ) b )
S₆₆ = 66/2 ( 2(7) + ( 66 - 1 ) 3 )
S₆₆ = 33 ( 14 + 65(3) )
S₆₆ = 33 ( 14 + 195 )
S₆₆ = 33 ( 209 )
S₆₆ = 6897 [ Opsi. C ]

[tex]~[/tex]