Answer:
1586
Explanation:
The first thing you want to do is find the min and max value of this.
You have your expression, 4i+7, which you use to plug your lowest number (1) and highest number (26) into in order to find the min and max.+
Min.: 4i+7 —>4(1)+7 = 11
Max.: 4i+7 —> 4(26)+7 = 111
Now you have your lowest and highest, you use the formula :
Sn= n (a1 + a2 /2)
** n= 26 in this case; a1 = 11; a2 = 111
Plug in your numbers:
S26 = 26 (11+111/2)
= 26(122/2)
=26(61)
=1586