How do I answer this

Question

f(x) = x - 3 (x + 4)^(1/2)

and am asked how to solve for x when y = -5

I have no idea how to do this and know that I could just solve it by guess and checking but I want to know how to do this algebraically when plugging in the -5 and trying to solve for x like so

-5 = x - 3 (x + 4)^(1/2)

and I don't know how to do that

also why is 22/7 pi???? is it just by luck??? kind of random but just have to know