Question

determine o 60 termo da pa (9, 13, 17, 21, )

Answer 1

$A_{n}=A_{1}+(n-1).R \\ \\ R=A_{2}-A_{1}=A_{3}-A_{2}=... \\ R=13-9=4 \\ \\ A_{60}=9+(60-1).4 \\ A_{60}=9+59.4 \\ A_{60}=9+236 \\ A_{60}=245$

Answer 2

a₁ = 9
a₂ = 13
r = 13 - 9 = 4
n = 60
    a₆₀ = a₁ + (n - 1) . r
    a₆₀ = 9 + (60 - 1) . 4
    a₆₀ = 9 + 59 . 4
    a₆₀ = 9 + 236
    a₆₀ = 245

Espero ter ajudado. Valeu!