Find the domain of the following function h(x,y) = sqrt(x-9y+5)?

Answer 1

Since sqrt(x) requires x≥0, therefore the domain of the function is such that:
x-9y+5≥0
equivalently:
9y≤x+5
or
dom h(x,y) = {x,y ∈ℝ | 9y≤x+5}