Square root of 16, and my plot basically shows it crosses at 4 and-- well, I think that's minus 4.

我的图清楚的显示这个函数,在4和-4两个点和x轴交合。

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x 4 x 4--possibilities, because I could have here, here, , , - 4 x 4 = 16.

x4x4种可能性,因为这有AGCU四种,这也是四种,4x4=16.

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