Question

Calcula la suma de terminos de la P.A 7; 10; 13; 16; 19; ....; 67​

Answer 1

Respuesta:

$a _{1} = 7 \\ a _{n} = 67 \\ r = 3$

$67 = 7 + (n - 1)3 \\ n= 21$

$suma = \frac{(a _{1} + a _{n} )}{r}(n) \\ = ( \frac{67 + 7}{3} )21 \\ = 37(21) \\ = 777$