Construct a valid third-degree equation
One possible third-degree equation is `y = x^3 + 2x^2 - 3x + 1`.
Complete the following task based on the instruction and optional input provided.### Instruction:
Construct a valid third-degree equation

### Output:
One possible third-degree equation is `y = x^3 + 2x^2 - 3x + 1`.