# Solve: f(x,y) = 65-x^2-y^2

## Question:

Solve:

{eq}f(x,y) = 65-x^2-y^2 {/eq}

## Equations in two variables

Whenever we are given equations in two variables we should try to solve them by plotting their graphs or understanding their curves.

We are going to do the same in this problem.

Given:

{eq}f(x,y) = 65-x^2-y^2 {/eq}

The solution of this equation is:

f(x,y) = 0

{eq}f(x,y) = 65-x^2-y^2 = 0 \\ x^2+y^2 = 65 {/eq}

This equation represents a circle around the origin (0,0) with radius {eq}\sqrt{65} {/eq}