I want to know the results of following equations.

x^{2}+ x +1 = y

In the above equation for 1 value of x there is 1 value of y. But for 1 value of y there are three values of x as it then becomes a 3rd degree equation.

1.If we go on substituting values for the variable x we get 1 value of y.

2.If we substitute values for y we get 3 values for x.

Aren't case 1 and case 2 supposed to yield the same result?