Read this and answer the question. If the question is unanswerable, say "unanswerable".

The Xbox 360's advantage over its competitors was due to the release of high profile titles from both first party and third party developers. The 2007 Game Critics Awards honored the platform with 38 nominations and 12 wins more than any other platform. By March 2008, the Xbox 360 had reached a software attach rate of 7.5 games per console in the US; the rate was 7.0 in Europe, while its competitors were 3.8 (PS3) and 3.5 (Wii), according to Microsoft. At the 2008 Game Developers Conference, Microsoft announced that it expected over 1,000 games available for Xbox 360 by the end of the year. As well as enjoying exclusives such as additions to the Halo franchise and Gears of War, the Xbox 360 has managed to gain a simultaneous release of titles that were initially planned to be PS3 exclusives, including Devil May Cry, Ace Combat, Virtua Fighter, Grand Theft Auto IV, Final Fantasy XIII, Tekken 6, Metal Gear Solid : Rising, and L.A. Noire. In addition, Xbox 360 versions of cross-platform games were generally considered superior to their PS3 counterparts in 2006 and 2007, due in part to the difficulties of programming for the PS3.

What are two prominent 360 exclusive franchises?
the Halo franchise and Gears of War