Question

从集合 $\{ -7, -5, -1, 1, 3 \}$ 中选两个数相乘，可能得到的最小乘积是

The smallest product one could obtain by multiplying two numbers in the set $\{ -7, -5, -1, 1, 3 \}$ is

$-35$

$-21$

$-15$

$-1$

$3$

知识点：最优化

负乘积来自负数乘正数；要最负，就让两个因数的绝对值尽可能大。

最负的乘积是 $(-7)(3) = -21$ 。

所以正确答案是 B。

A negative product comes from multiplying a negative number by a positive number, and it is most negative when both factors are largest in size.

The most negative product is $(-7)(3) = -21.$

Thus, the correct answer is B .