If $$f(x) = {{x - 2} \over {x + 2}}$$, x $$\ne$$ $$-$$2, then what is f^$$-$$1(x) equal to ?

If f(x) = log₁₀ (1 + x), then what is 4f(4) + 5f(1) $$-$$ log₁₀ 2 equal to ?

For the following two (02) items:
Consider the function
$f(x)=\frac{x}{1-x}(x>0,x\ne 1)$

What is $\frac{f(x)}{f(x+1)}$ equal to?

For the following two (02) items:
Consider the function
$f(x)=\frac{x}{1-x}(x>0,x\ne 1)$

What is $ (1-x)f(\sqrt{x})+xf(\sqrt{x}+1)$ equal to?