要（よう）するに is an expression in Japanese used to highlight important information in a similar way to 'to sum up', 'in summary', or 'in short' in English. It is a combination of the する-Verb 要（よう） 'to need', or 'to require', and に. Literally it means something similar to 'as for what's necessary (A)'.
This is a phrase that will only ever take the initial position in a sentence, before expressing a condensed version of what has previously been said.

• 要（よう）するに、あなたは履歴書（りれきしょ）に嘘（うそ）を書（か）いたと言（い）う事（こと）ですね。
  In short, this means that you lied on your resume, didn't you?
• 要（よう）するに、小麦（こむぎ）が入（はい）っている食（た）べ物（もの）は食（た）べれないと言（い）う事（こと）ですね？
  So, in summary, I can't eat any food that has wheat in it?
• 要（よう）するに、俺（おれ）はあいつに使（つか）われていたと言（い）うことだ。
  In short, I was being used by him.