Tylerpinkston Tylerpinkston
  • 18-10-2016
  • Mathematics
contestada

what is the sum of the last four terms of the series 7+9+11+...21

Respuesta :

SJ2006
SJ2006 SJ2006
  • 18-10-2016

For sake of convenience, reverse the series, then it would be:

21,19,17.....7

a=21, d = -2,

s(4) = 4/2 (21+15)

s(4)=2(36)

s(4) = 72


Answer Link

Otras preguntas

claustrophobia is an example of a(n)​
What is the solution set of 4x^2 -5x +1 =0
The black night was split open like the coconut
A new landowner is interested in constructing a fence around the perimeter of her property. Her property is 1,080√30 feet wide and 500√20 feet long. What is the
What is the explicit formula for this sequence -7, -4, -1, 2, 5
You encounter a solution that is acidic and you decide to test it by adding a small amount of a strong acid. The pH lowers slightly but is approximately unchang
Add (7x^2-3x)+(5x-6)
how do you solve this equation 26x=74
What was the first official pair of sister cities?
When Mrs. Jameson says "It (the desert) won't leave you cold," what does she mean?