Question

Escrever a P.A (a1,a2,a3...) sabendo que a11=18 e a15=30

Answer 1

$a_1_1= a_1+10r\\ a_1_5 = a_1+14r\\\\ 18 = a_1+10r\\ 30 = a_1+14r\\\\ a_1 = 10r-18\\\\ 10r-18+14r = 30\\\\ 24r = 48\\\\ \boxed{r=2}$

$a_1_1 = a_1+10r\\\\ 18 = a_1+20\\\\ \boxed{a_1=-2}\\\\\ \boxed{a_2 = 0}\\\\ \boxed{a_3 =2}$

PA (-2,0,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30)

Answer 2

Resposta:

PA = ( -12, -9, -6, -3, 0, 3, 6, 9, 12, 15, 18, 21, 24, 37, 30)

Explicação passo a passo: