Answer:
You have to replace x with 3 and then with 2+h
Step-by-step explanation:
[tex]f(x)=\frac{1}{x^{2}-3} \\f(3)=\frac{1}{3^{2}-3} \\f(3)=\frac{1}{9-3} \\f(3)=\frac{1}{6} \\\\f(2-h)=\frac{1}{(2-h)^{2}-3} \\f(2-h)=\frac{1}{2^{2}-4h+h^{2}-3} \\f(2-h)=\frac{1}{h^{2}+4h+1}[/tex]