sar2ietrelorev sar2ietrelorev

25-05-2016
Mathematics

contestada

What is the sum of the first 45 terms of the following sequence? 20, 18, 16, . . .
a. 1,080
b. 1,420
c. 1,530
d. 1,980

Relax

Respuesta :

Аноним Аноним

26-05-2016

Sn = (a1+an)* n / 2
an = a1+d(n-1)

d = 18-20 = -2
a45 = a1+d(45-1) = 20 - 2*(45-1) = -68
S45 = (20-68)*45/2 = -1080

Answer Link

Otras preguntas

Solve by elimination. 6x - y = -5 and 4x - 2y = 6

Round 656.692169912 to 1 decimal place. I am so confused.

Which task, performed by systems developers, will most likely ensure that end users accept a new system?

Which largely Muslim countries are located in Southeast Asia?(Select all that apply)MongoliaVietnamMalaysiaIndonesiaChina

Solve the system of equations using the substitution method (pic) x=y=

URGENT! PLEASE HELP ME ASAP!!Which was not a common religious belief of both Sunnis and Shiites?Frequent fasting and meditation is required to commune with Alla

In the traditional rhyme, how many mice were blind?

I think of a number , half it then subtract four

Give two examples of how Jem has grown in Part 1 of the novel.

markin brainiest !!!