Perhatikan baris bilangan berikut :12,20,30,42,56 Suku ke 12 dari bilangan tersebut adalah

12 = 3*4 → (1+2)(1+3)
20 = 4*5 → (2+2)(2+3)...
30 = 5*6
42 = 6*7
56 = 7*8
Un = (n+2)(n+3)

jadiiii
U12 = (12+2)(12+3)
= 14*15
= 210 ✔️

semoga jelas dan membantu

U1 = 12 = ( 3 × 4 )
U2 = 20 = ( 4 × 5 )
U3 = 30 = ( 5 × 6 )

Un = ( n + 2 ) ( n + 3 )

U₁₂ = ( 12 + 2 ) ( 12 + 3 )
U₁₂ = ( 14 ) ( 15 )
U₁₂ = 210

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