no 1 sampe 5 dong pake cara

2. Un = a + (n - 1) × b
U(2) = 1 + (2 - 1) × 4
U (2) = 5

2.1,5,9,13,17,21
5.3 6 9 12 15 18 21 24
a=3 b=3
un=a +(n-1) b
u8=3 +(8-1)3
=3+(7)×3
=3+21
=24