Answer
A nonlinear equation is an equation in which one equation cannot be expressed in the form $ Ax+By=C $. The example is $\left\{ \begin{align}
& {{x}^{2}}+9{{y}^{2}}=5 \\
& xy=4
\end{align} \right.$.
Work Step by Step
We know that a system of nonlinear equations is a system of equations where one or more terms have a variable of degree of two or higher in one of the equations.
Let us consider variables x and y.
Then, for example:
The following are some systems of nonlinear equations:
(i) $\left\{ \begin{align}
& {{x}^{2}}-{{y}^{2}}=5 \\
& x+y=7
\end{align} \right.$
(ii) $\left\{ \begin{align}
& {{x}^{2}}+9{{y}^{2}}=5 \\
& xy=4
\end{align} \right.$
