plz help I have no idea what I'm doing.
What is the sum of the series?

Answer:
30
Step-by-step explanation:
Substitute j = 1, 2, 3, 4, 5 into 2j and sum, that is
sum = (2 × 1) + (2 × 2) + (2 × 3) + (2 × 4) + (2 × 5)
= 2 + 4 + 6 + 8 + 10 = 30