tolong bantu soal yg ini kak pake caranya ya please

Un = a + (n-1)b
U4 = 5 + (4-1)b
29 = 5 + 3b
-3b = 5-29
b = 8

U14 = 5 +(14-1)8
U14 = 5 + 13 x 8
U14 = 5 + 104
U14 = 109

9.
U1+U5 = 22
22= a+a + 4b
2a + 4b = 22

U9 = a +(n-1)b
29 = a + (9-1)b
a+ 8b =29

2a + 4b = 22
a + 8b = 29
Eliminasi

2a + 4b = 22
2a + 16b = 58
-12b = -36
b = 3

2a + 4b = 22
2a + 12 = 22
2a = 10
a = 5

77 = 5 + (n-1)3
72 = 3n-3
69 = 3n
n = 23


10.