If I multiply 85*-58 on my calculator I get -4930. I don't know how that can be "simplified." And I don't know how you came up with 4.93. If your prof watches significant figures, and these are measurements of some kind, I would write -4930 as -4.9 x 10^3. Writing as an integer I would write -4930 and if the decimal I would write -4930.0. You may want to clarify the question if this answer is not sufficient. If you are keying in your answer to a database, I suspect the negative sign was missing and your number isn't nearly large enough.
