In order to translate this phrase into an algebraic expression, first let's understand how to proceed with each part of the phrase.
First we have a difference of two things, so we will have an expression like "a - b".
The first term in the difference is "nine plus a number x", so the first term is "9 + x"
The second term in the difference is four, so it's just "4".
Therefore the final expression will be: