Answer:
[tex]f(x)= \frac{3}{x+2}- \sqrt{x-3}[/tex]
the given function has domain
x+2≠0
x≠ -2
x-3≥0
x≥3
That is , x ∈ [3,∞]
Now, calculating ,f (19)
[tex]f(19)= \frac{3}{19+2}-\sqrt{19-3}\\\\ = \frac{3}{21} - \sqrt{16}\\\\ f(19)=\frac{1}{7}-4\\\\=\frac{1-28}{7}\\\\=\frac{-27}{7}[/tex]
[tex]f(19)=-[3\frac{6}{7}][/tex]