What you meant was range. The range scales from top to bottom. You can know this by graphing and practicing memorizing these function's domain and range.
Function: Range:
f(x) = -√x y ≤ 0
p(x) = ∛2-x All real numbers
w(x) = 2 + √x y ≥ 2
r(x) = -2 + √2-x y ≥ -2
k(x) = 2 - √x y ≤ 2
v(x) = √-x y ≥ 0
