Let x be the sum of a and b.

设x为a加b之和。

《牛津词典》

Let x be the equal of y.

设x等于y。

《新英汉大辞典》

The first person let me go ahead and check out before him because of (x); other people did the same thing because of f(x). The essence of (x) is unknown.

第一个让我先结账的人是因为（x），而其他人这么做是因为（x），而这个x却是未知的。

youdao

Let me suppose X is 1. So I'll take X to be 1, then Y should be 2. Right?

假设X是1，将1代入x，然后Y应该为2，对吗？

youdao

Doctor: Let me see, I think you need an X-ray exam.

医生：让我看一下，我觉的你得做一个x光检查。

youdao

Let X denote the studied flood flow variable and (?)

令x表示所研究的洪水变量，(？)

youdao

Let X denote the studied flood flow variable and (?)

令x表示所研究的洪水变量，(？)

youdao