Another way to say f(x) is y, so y=0 at -2 and 10. :)
This shape is trapezoid
top of the trapezoid is 10 (12-2)
and the bottom is 4 (6-2)
the height in 3 (3-0)
so the area will be

the area is 21
Y = the square root of x minus 2 is portrayed in the file attached below.
As you can see, the domain (x value) begins at 2. We can use interval notation to say that the domain is [2, infinity) Infinity because it will stretch out to infinity. While the range will be [0,infinity) (message me if you don't recognize these concepts please.)