kak tolong ya yang jago mtk tolong bantu

silahlan di cek jawabannya

U1 = 1
b = 3 - 1 = 2
n = 6

1. Sn = 1/2n [ 2U1 + ( n -1 )b ]
= 1/2(6)[ 2(1) + ( 6 - 1 )2 ]
= 3 [ 2 + (5)2 ]
= 3 [ 2 + 10 ]
= 3 [ 12 ]
= 36

2. U10 = a + ( n - 1 )b
= 1 + ( 10 - 1 )2
= 1 + ( 9 )2
= 1 + 18
= 19

3. Un = a + ( n - 1 )b
= 1 + ( n - 1 )2
= 1 + 2n - 2
= 2n - 1

semoga membantu ^^