Use sigma notation to represent the sum of the first seven terms of the following sequence: −4, −6, −8, …
a. the summation from n equals one to 7 of quantity negative 2 minus 2 times n
b. the summation from n equals one to 7 of quantity negative 4 plus 2 times n
c. the summation from n equals one to 7 of quantity negative 2 minus 4 times n
d. the summation from n equals one to 7 of quantity negative 2 plus 2 times n