u3 = 9 u6=15 u15=? berapakah u1?

u3 = 9 = a + (3-1) b = 9
u6 = 15 = a + (6-1) b = 15

u3 = a + 2b = 9
u6 = a + 5b = 15
lalu pakai cara eliminasi
-3b = -6
3b = 6
b = 6/3 = 2

a + 2b = 9
a + 2×2 = 9
a + 4 = 9
a = 9-4 = 5

U15 = a + (15-1) b
U15 = 5 + 14×2
U15 = 5 + 28
U15 = 33

Semoga Bermanfaat