an nonlinear equation can be y=3x m dose not equal 7
A nonlinear equation does not produce a straight line and the exponent is to the second power or more. x square plus 3y =5 is an example of a nonlinear equation.
If you mean y = x2, then yes, it is nonlinear.
Without an equality sign the given expression is not an equation
None because without an equal sign it's not an equation but some kind of an algebraic expression.
In a nonlinear equation, each variable must only have one solution.
If you mean y = 2x then it is a straight line equation