# What is the domain and range of x= -sqrty ?

Domain : <0;+oo)
Range: (-oo;0>
Domain is the subset of $\mathbb{R}$ for which the formula can be calculated. In this case there is a square root in the formula, so $y$ must be greater than or equal to zero.
To calculate the range you have to see, that the value is always less tan or equal to zero, so the range is set of all negative number and zero, because $y \left(0\right) = - \sqrt{0} = 0$