"The function is decreasing":
This means the slope of the function will be negative at the given point. Anywhere the line is going down, from left to right, is decreasing. This eliminates choices A and C.
"The function is concave down":
This means the curve of the function will be open down (think of an upside down u). This eliminates choice E.
"f(x)>0":
This is anywhere the curve is above the x axis. This eliminates choice D.
The answer is Choice B) x=2.
Hope this helps!!
