Rewrite this sentence so that it begins with an adverb.

the members of the orchestra tuned their instruments.

having found their seats, the members of the orchestra began to tune their instruments.
the instruments were tuned by the members of the orchestra.
softly, the members of the orchestra tuned their instruments.
tuning their instruments were the members of the orchestra.

Based on the given sentence above, the correctly rewritten sentence for it so that it begins with an adverb would be the first sentence. "Having found their seats, the members of the orchestra began to tune their instruments." Putting an adverb at the beginning of the sentence is putting it at the start of the subordinate clause and starts with a past participle. Hope this answer helps. 

When your given a formula it is made available to you once you know all the possible variables.

hope this works.