Need some hlp with my discrete math homework summation

Question

Use the summation notation to rewrite the following expression.

(7 − 13) − (7 − 23) + (7 − 33) − (7 − 43) + (7 − 53) − (7 − 63) =

6

k = 1

  

 

 

Answer 1

(7 − 1³) − (7 − 2³) + (7 − 3³) − (7 − 4³) + (7 − 5³) − (7 − 6³) =

6 + 1 - 20 + 57 - 118 + 209 =135

This isn't between 1 and 6.