Write the sum (6^4+6)+(6^5+6)+(6^6+6)+(6^7+6) in summation notation in terms of 𝑘. (Use symbolic notation and fractions where needed.)

Question

the summation they gave was ∑ n = 7 k = 4 ( )

not sure how to solve for what to put in the parentheses

Answer 1

Σ⁷_k=4 (6^k + 6)