计算 $\dfrac{-(-11.8)-\sqrt{(-11)^2-7\times16\times(-40)}}{2\times16}$。 答案 ... 一个礼堂里有 800 人（精确到百位）。 写出此时礼堂里可能有的最少人数。 答案 ... 人

1. Simplify the signs and calculate the value of the expression

$\frac{-(-11.8)-\sqrt{(-11)^2-7\times16\times(-40)}}{2\times16}$
$=\frac{11.8-\sqrt{121+4480}}{32}$
$=\frac{11.8-\sqrt{4601}}{32}$
$=\frac{11.8-67.830\ldots}{32}$
$=-1.7509\ldots$
$\approx -1.75$

1. Find the minimum whole number that rounds to 800 to the nearest hundred

To round to $800$ to the nearest hundred, the number must be at least halfway between $700$ and $800$:

$750$

Hence, the minimum possible number of people is $750$.