Answer
$ 7, 0, \sqrt {35} , \sqrt \frac{21}{2} $
Work Step by Step
$f(x,y,z) = \sqrt {49-x^2 - y^2 - z^2} $
a) $f(0,0,0) = \sqrt {49} = 7 $
b) $f(2,-3,6) = \sqrt {49-4-9-36} = 0 $
c) $ f(-1,2,3) = \sqrt {49-1-4-9} = \sqrt {35} $
d) $ f(\frac{4}{\sqrt 2}, \frac{5}{\sqrt 2}, \frac{6}{\sqrt 2}) = \sqrt {\frac{21}{2}} $
