ExplanationThis function defines a made-up symbol, rather than using traditional notation such as f(x).

First, translate the function:

\(#x = \sqrt{x+2}\)

The square root of any value greater than or equal to 0 is the non-negative square root of the value.

That is, the square root of 4 is just +2, not –2. Thus:

\(#7 =\sqrt{7+2} =\sqrt{9} = 3\)

\(#(-1) = \sqrt{-1+2}= \sqrt{1}= 1\)

Finally, \(#7 - #(-1) = 3 - 1 = 2\).

_________________

Sandy

If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test