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ASAP

What is the sum of the terms of the series (use the formula): 7 + 11 + 15 + . . . + 35

Sn = n 2(a1 + an) Sn = a1(1 - rn) 1 - r S = a1 1 - r

with work

Respuesta :

crisforp

Answer:

a1 = 7;

r = a2 - a1; r = 11- 7 = 4

an = 35;

an = a1 + (n-1)r; 35 = 7 + (n-1)4;28=(n-1)4;n-1=7;n=8;

Sn = (a1+an)n/2;

S8 = (7+35)8/2;

S8=42x8/2;

S8=21x8;

S8= 168;

Step-by-step explanation:

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