what is the sum of the finite arithmetic series (-5)+0+5+10+ ......+65a. 900b. 455c. 450d. 445
Question
Answer:
If you want to solve this problem using formulas, there are two important formulas:t1 = first term = -5 tn = nth term = last term = -5n = numbr of termsSn = sum of the n termstn = t1 + (n - 1)d ---> 65 = -5 + (n - 1)(5) 65 = -5 + 5n - 5 65 = -10 + 5n 75 = 5n n = 15Sn = n(t1 + tn)/2 ---> Sn = 15(-5 + 65)/2 Sn = 450So ur answer rounds up to 450
Letter c:)hope i helped
~Luis
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