2007-03-25 14:18:34 · 5 respostas · perguntado por Feh 1 em Ciências e Matemática ➔ Matemática
a1 = -6
an = -66
r = -9 -(-6) = -3
n = ?
an = a1 + (n - 1)r
-66 = -6 + (n - 1) * -3
-66 + 6 = -3n + 3
-60 - 3 = -3n
-63 = -3n
n = 63/3
n = 21
PA = {-6, -9, -12, -15, -18, -21, -24, -27, -30, -33, -36, -39, -42, -45, -48, -51, -54, -57, -60, -63, -66}
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2007-03-25 15:47:12 · answer #1 · answered by aeiou 7 · 0⤊ 0⤋
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2015-01-08 15:25:29 · answer #2 · answered by MIYAMURA 1 · 0⤊ 0⤋
an = a1 + (n-1)r
-66=-6-3n+3
3n=66-6+3
3n=66-3
3n=63
n=21
n = nº d termos
a1 = -6
an = -66
r= -3
2007-03-25 14:44:49 · answer #3 · answered by Fê 2 · 0⤊ 0⤋
sei lá
2007-03-25 14:26:56 · answer #4 · answered by Santos 2 · 0⤊ 1⤋
O NUMERO DE TERMOS DESSAS P.A=22 TERMOS
2007-03-25 14:25:07 · answer #5 · answered by RENATO 3 · 0⤊ 1⤋