What is the following difference? 11 sqaure root 45 - 4 sqaure root 5

Witch represents the inverse of the function f(x)=1/4x-12

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

Suppose that the function f is defined. , for all real numbers, as follows. _ \ 1/4x² -4 if x≠ -2 f(x)=< /_-1 if x=-2 find f(-5), f(-2), and f(4)