You'd pull out your pencil and paper, you can do it as a matrix inversion if you know how to do that, or you can just simply do substitution of one equation into another to solve it.

你知道你在小学的时候是怎么做的对吧？,你拿出你的笔和纸,如果你会的话,你可以解一个方程组,或者你可以单纯地。

麻省理工公开课 - 计算机科学及编程导论课程节选

Maybe you didn't realize that they are just simultaneous equations that you solve.

也许你并没有意识到,它们其实就是你们平时解的方程组

耶鲁公开课 - 基础物理课程节选