Get our expert's

answer on brainly

SEE EXPERT ANSWER

Get your **free** account and access **expert** answers to this and **thousands** of other questions.

See more answers at brainly.com

yep

or you could factorise quadratically but that would take way longer

Why do I add the 1s since there is no index k?

obviously

the k can be omitted, actually.

How?

\[\sum_{k=1}^{n}=\sum_{1}^{n}\]

Ok, now I think I get it.
Thank you Shadowys for your help.

You're welcome :)