Solving a Cubic Equation by a general formula





At this web page you are able to solve a cubic equation.
A cubic equation or an equation of the third degree can
be described by the following general expression:

F(X) = AX3 + BX2 + CX + D

X is an unknown real or complex number.
F(X) is a function of X. May also have the symbol 'Y'.
A, B, C and D are all real numbers of constants.

If you set F(X) = 0, the cubic equation can be solved.


Example

X3 + X2 - X - 1 = 0

This equation has got three real roots:  X1 = -1,
X2 = -1 and X3 = 1.
I've drawn the graph of F(X) = X3 + X2 - X - 1, [-2,2]:

A graph of F(X) = X3 + X2 - X - 1

AX3 + BX2 + CX + D = 0


Calculation

Input the values of A, B, C and D.
To start the calculation please press the button.


A =     B =     C =     D = 

   


X1 = 
X2 = 
X3 = 



Algebra