How to make sentences more formal

How to make sentences more formal.
Using the Passive. Removing the ‘I’ from your writing.
Sometimes when you are writing you may not want to use words like: I, you,
someone, the author, the reader, researchers or keep repeating the names of
writers you have referenced.
It is possible to write the same sentence using a grammatical form called the
passive. You probably use it all the time but don’t know its name.
The author wrote the report
The report was written (by the author)
As you can see ‘the author’ doesn’t really give you any extra information, it is
obvious it was written by the author in other words the person who wrote it, so
the second sentence is a better one.
Write these sentences using the Passive:
Scientists discovered the cure at the turn of the century.
Researchers carried out the research in Canada.
Soldiers won the war in 1945.
Politicians signed the treaty in 1921.
Lawyers argued the case in court.
The goalkeeper saved the penalty
Someone stole my car.
Someone told me you were to blame.
The cure was discovered at the turn of the century.
The research was carried out in Canada.
The war was won in 1945.
The treaty was signed in 1921.
The case was argued in court.
The penalty was saved.
My car was stolen.
I was told you were to blame.