I need to convert regular formula to Excel formula format

Hello all!

I need to perform a conversion on some data (lots of data), using the following formula, but on an Excel spreadsheet, and I have no idea how to convert it to Excel formula format:

formulas.JPG

My input (data I already know) is: X, Y, Z, Xn, Yn, Zn.
What I need to find out: L*, a*, b*

Source of the formulas.

Any help will be greatly appreciated.

Thanks in advance.

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