## Precalculus (6th Edition) Blitzer

We get the equation ${{x}^{2}}+y=10$ that defines $y$ as a function of $x$.
The equation is given below: ${{x}^{2}}+y=10$ …… (I) So, from equation (I), $y=10-{{x}^{2}}$. Thus, for every value of $x$, there is exactly one value of $y$. Thus, the equation defines $y$ as a function of $x$. Hence, we get the equation ${{x}^{2}}+y=10$ that defines $y$ as a function of $x$.