Write the sum using summation notation, assuming the suggested pattern continues.
-9 - 3 + 3 + 9 + + 81

Sum of the sequence will be 648

Step-by-step explanation:

The given sequence is representing an arithmetic sequence.

Because every successive term of the sequence is having a common difference d = -3 - (-9) = -3 + 9 = 6

3 - (-3) = 3 + 3 = 6

Since last term of the sequence is 81

Therefore, by the explicit formula of an arithmetic sequence we can find the number of terms of this sequence

where a = first term of the sequence

d = common difference

n = number of terms

81 = -9 + 6(n - 1)

81 + 9 = 6(n - 1)

n - 1 =

n = 15 + 1 = 16

Now we know sum of an arithmetic sequence is represented by

Now we have to find the sum of the given sequence

              = 8[-9 + 90]

              = 8×81

              = 648

Therefore, sum of the terms of the given sequence will be 648.

step-by-step explanation:

what grade level is this? need to know so i can look in my old textbooks!