When a quadratic order polynomial is of the type ax2 + bx + c = 0 (a ≠  0), we call it a Quadratic Equation. The general version of the Quadratic Equation is now ax2 + bx + c = 0 (a ≠ 0), where ‘a', ‘b' and ‘c’ are constants i.e. numbers. The constant ‘b’ and ‘c’ can also be equal to zero but ‘a’ cannot be zero.