Answer:
S18 = 288
Step-by-step explanation:
find the first and last term.
n = 1
a1 = 2 x 1 - 3
a18 = 2 x 18 - 3
(simplify the expression)
a1 = -1
a18 = 33
(use the formula for the sum of a finite arithmetic series)
a1 + a18
S18 = 18 x ---------------------
2
(use the substitute) substitute -1 for a1 and 33 for a18
-1 + 33
S18 = 18 x ---------------------
2
simplify the expression and ur done hope this helped x
ps. wheres my head :)
