Notasi Sigma nya berapa?

Materi Notasi Sigma

[tex] 2 \sum^{n}_{k=1} k(2k + 5) + 2 \sum^{n}_{k=1} (k + 3) + 3n \\
= \sum^{n}_{k=1} 2k(2k + 5) + \sum^{n}_{k=1} 2(k + 3) + \sum^{n}_{k=1} 3 \\
= \sum^{n}_{k=1} (4k^2 + 10k + 2k + 6 + 3)
= \sum^{n}_{k=1} (4k^2 + 12k + 9) [/tex]