Final answer:
To make a sentence more formal, you can change "it's" to "it is", "undertake" to "go for", or "job" to "gig".
Step-by-step explanation:
The subject of this question is English. The student is asking how to put a sentence in formal style. To make the sentence more formal, the best revision is to change "it's" to "it is". This increases the formality of the sentence. Another option could be changing "undertake" to "go for" which is a more formal phrase. Lastly, instead of using "job", the word "gig" could be used, which is also more formal.
Learn more about Formal Writing