Mammoth Printing Company charges a fee of $28 to print an overized poster, and $7 for each color of ink used in the poster. Colossal Printing charges a fee of $34 to print an oversized poster and $5.50 for each color of ink used. If x represents the number of colors of ink used to print poster, what are all the values of x for which Mammoth Printing Company would charges more to print the poster than Colossal Printing?