Tentukan rumus ke-n tentukan U79 dan U151 A. 7, 9, 11, 13,... B. 64, 62, 60, 58,...

A.
a = 7
B = 9-7 = 2

Un :
= a + (n-1) x b
= 7 + (n-1) x 2
= 7 + 2n -2
= 5 + 2n

U79 :
= a + 78b
= 7 + 78x2
= 7 + 156
= 163

U151 :
= a + 150b
= 7 + 150x2
= 7 + 300
= 307

B.
A = 64
b = 62-64 = -2

Un :
= a + (n-1) x b
= 64 + (n-1) x -2
= 64 -2n + 2
= 66 -2n

U79 :
= a + 78b
= 64 + 78 x -2
= 64 + (-156)
= -92

U 151 :
= a + 150b
= 64 + 150 x -2
= 64 + (-300)
= -236