Sagot :
Integers are basically digits in the number line. Integers can be either positive or negative. Because 9 and 27 are positive integers you will simply have to look for the sum of the even numbers between 9 and 27 which are: 10, 12, 14, 16, 18, 20, 22, 24 and 26.
Add all of those together and you get: 162
given: Asub1=10
AsubN=26
n=9
Ssub9=9/2(10+26)
=9/2(36)
=9/2 × 36/1
=324/2
Ssub9=162
AsubN=26
n=9
Ssub9=9/2(10+26)
=9/2(36)
=9/2 × 36/1
=324/2
Ssub9=162