Question

F(x)= √x-5. find f-2

Answer 1

For this case we have:

Be a function of the form $y = f (x)$

Where:

$f (x) = \sqrt {x-5}$

If we want to find f (-2), we substitute $x = -2$, then:

$f (-2) = \sqrt {-2-5}\\f (-2) = \sqrt {-7}$

Since we have a negative root, the result will be given by complex numbers. By definition:

$\sqrt {-1} = i$

So:

$f (-2) = \sqrt {7} i$

Answer:

$f (-2) = \sqrt {7} i$