Question

Calcule o 15º termo geral da progressão
aritmética (10, 17, 24) dessa PA.
Lembre-se da formula: na = a1 + (n-1).r
a) an = 51
b) an = 24
c) an = 110
d) an = 108

Answer 1

$\Large\boxed{\begin{array}{l}\sf a_1=10\\\sf r=17-10=7\\\sf a_{15}=a_1+(15-1)\cdot r\\\sf a_{15}=a_1+14r\\\sf a_{15}=10+14\cdot7\\\sf a_{15}=10+98\\\sf a_{15}=108\end{array}}$