Question

Determine o vigésimo termo da P.A. (3, 5, 7, ...)

Answer 1

3,5,7,9,11,13,15,17,19,21,23,25,27 ,29,31,33,35,37,39,41

Answer 2

a₁ = 3
a₂ = 5
a₃ = 7
n = 20
r = 5 - 3 = 2
             a₂₀ = a₁ + (n - 1) * r
             a₂₀ = 3 + (20 - 1) * 2
             a₂₀ = 3 + 19 * 2
             a₂₀ = 3 + 38
             a₂₀ = 41

Espero ter ajudado. Valeu!