Take these two equations, put an equal sign between them, replace this PR throughout with X, I'm going to have one equation and one unknown and that even the math phobics in the audience did in high school.

在这两个方程中间加个等号,将这里的Pr换成X,就会得到一个等式和一个未知数,剩下的问题,大家高中的时候就该回做了吧

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