9514 1404 393
Answer:
B, D
Step-by-step explanation:
The quadratic expands to ...
(2n -1)² = (2n)² +2(2n)(-1) +(-1)² = 4n² -4n +1
The coefficients can be factored out of the sum, so ...
∑(4n²) = 4∑n² for example
The sum of 60 ones is 60:
[tex]\displaystyle\sum_{n=1}^{60}{1}=1+1+1+\dots+1=60[/tex]
So, the sum can be written as ...
[tex]\displaystyle\sum_{n=1}^{60}{(2n-1)^2}\\\\=\boxed{4\sum_{n=1}^{60}{n^2}-4\sum_{n=1}^{60}{n}+\sum_{n=1}^{60}{1}}\\\\=\boxed{4\sum_{n=1}^{60}{n^2}-4\sum_{n=1}^{60}{n}+60}[/tex]
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It appears that the key to choosing the correct answers is paying attention to signs.
