Step 1 of this proof is which of the following ? reasoning, arguments, and proof, part 1

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

Ben works in his dads bakery packing bagels each package can have no more then 16 bagels 3/4 of the bagels in each package are plain what other fractions could represent the part of the bagels in each package that will be plain

Asap! i need this done today and i really don’t understand it. some one ! will mark