Are this processor work in this motherboard?

According to the manufacture's website, yes, the Duron 1.8G is supported.

http://www.gigabyte.com.tw/Support [...] uctID=1361


CPU Support List
Motherboard Model GA-7DX
Vender Model System
Bus(MT/s) 266
AMD K7 Sempron 3000+ 333 N/A
AMD K7 Sempron 2800+ 333 N/A
AMD K7 Sempron 2600+ 333 N/A
AMD K7 Sempron 2500+ 333 N/A
AMD K7 Sempron 2400+ 333 N/A
AMD K7 Sempron 2300+ 333 N/A
AMD K7 Sempron 2200+ 333 N/A
AMD AthlonXP 3200+(Barton,.13u) 400 N/A
AMD AthlonXP 3000+(Barton,.13u) 400 N/A
AMD AthlonXP 3000+(Barton,.13u) 333 N/A
AMD AthlonXP 2800+(Barton,.13u) 333 N/A
AMD AthlonXP 2600+(Barton,.13u) 333 N/A
AMD AthlonXP 2500+(Barton,.13u) 333 N/A
AMD AthlonXP 2700+(Thoroughbred,.13u) 333 N/A
AMD AthlonXP 2600+(Thoroughbred,.13u) 333 N/A
AMD AthlonXP 2600+(Thoroughbred,.13u) 266 OK
AMD AthlonXP 2400+(Thoroughbred,.13u) 266 OK
AMD AthlonXP 2200+(Thoroughbred,.13u) 266 OK
AMD AthlonXP 2100+(Thoroughbred,.13u) 266 OK
AMD AthlonXP 2000+(Thoroughbred,.13u) 266 OK
AMD AthlonXP 1900+(Thoroughbred,.13u) 266 OK
AMD AthlonXP 1800+(Thoroughbred,.13u) 266 OK
AMD AthlonXP 1700+(Thoroughbred,.13u) 266 OK
AMD AthlonXP 1600+(Thoroughbred,.13u) 266 OK
AMD AthlonXP 2100+(Palomino,.18u) 266 OK
AMD AthlonXP 2000+(Palomino,.18u) 266 OK
AMD AthlonXP 1900+(Palomino,.18u) 266 OK
AMD AthlonXP 1800+(Palomino,.18u) 266 OK
AMD AthlonXP 1700+(Palomino,.18u) 266 OK
AMD AthlonXP 1600+(Palomino,.18u) 266 OK
AMD AthlonXP 1500+(Palomino,.18u) 266 OK
AMD AthlonXP 1500+(Palomino,.18u) 200 OK
AMD Palomino AHD 1200+(.18u) 266 OK
AMD Palomino AHX 1200+(.18u) 266 OK
AMD Palomino AHD 1000+(.18u) 266 OK
AMD Athlon 1.4G 266 OK
AMD Athlon 1.4G 200 OK
AMD Athlon 1.33G 266 OK
AMD Athlon 1.3G 200 OK
AMD Athlon 1.2G 266 OK
AMD Athlon 1.2G 200 OK
AMD Athlon 1.133G 266 OK
AMD Athlon 1.1G 200 OK
AMD Athlon 1.0G 266 OK
AMD Athlon 1.0G 200 OK
AMD Athlon 950 200 OK
AMD Athlon 900 200 OK
AMD Athlon 850 200 OK
AMD Athlon 800 266 OK
AMD Athlon 800 200 OK
AMD Athlon 750 200 OK
AMD Athlon 700 200 OK
AMD Athlon 650 200 OK
AMD Duron 1.8G 266 OK
AMD Duron 1.6G 266 OK
AMD Duron 1.4G 266 OK
AMD Duron 1.3G 200 OK
AMD Duron 1.2G 200 OK
AMD Duron 1.1G 200 OK
AMD Duron 1.0G 200 OK
AMD Duron 950 200 OK
AMD Duron 900 200 OK
AMD Duron 850 200 OK
AMD Duron 800 200 OK
AMD Duron 750 200 OK
AMD Duron 700 200 OK
AMD Duron 650 200 OK
AMD Duron 600 200 OK

I don't fully understand what you are asking.

The processor is a 1.8ghz (1800 mhz) processor. If the motherboard supports it, it will run at that speed with a 266mhz bus and a multiplier of 13.5. The processor uses double data rate therefore the actual bus speed is 133 (133 x 13.5 = ~1800).

I want to know are this processor run in 3000MHz or not, becouse I read in Gigabyte site that he is possible....

That would be a MASSIVE overclock, I wouldn't count on it. It's designed to run at 1800, a moderate overclock would put you at 1900-1950, and anything beyond that you'd be starting to get risky unless you know what you're doing.