Find the Sum Using the Formulas for the Sums of Powers

Multiple Choice

Find the sum using the formulas for the sums of powers of integers.​ $$\sum _ { i = 1 } ^ { 7 } \left( 5 i - 8 i ^ { 3 } \right)$$ ​

A) -784
B) -3,136
C) 4,200
D) 5,600
E) -6,132