For f(x)=1/x^2-3
Find
A) f(3)
B) f(2-h)
If f(x)=1/x^2-3, then f(3) = 1 / 3^2 - 3. The exponentiation here must be carried out first: f(3) = 1/9 - 3. Then f(3) = 1/9 - 27/9 = -26/9
If f(x)=1/x^2-3, then f(2-h) = 1 / [2-h]^2 - 3. This result may be left as is or expanded. In expanded form, we have:
1
f(2-h) = ------------------ - 3
4-4h +h^2