In p.251, "Introduction to statistics and probability for engineers and scientists, Sheldon M.Ross, 6th edition", I found this sentence:
By equating to zero, we obtain that the maximum likelihood estimate lambda_hat equals (some value).
For which the author means: To equate some equation (in previous page of the book) that contains lambda_hat (the so-called maximum likelihood estimate) to zero to solve for lambda_hat.
It's not clear to me that this is a case of bad grammar, a typo or a usage of the implicit object or something I'm being unaware of?
Also I couldn't find in any popular online dictionary such phrase "By equating to (something)".