Solving a cubic equation: Cardan's method

Learn the method of solving a cubic equation in the form, ax^3+bx+c=0.
The square term must be absent or else we have to use transformation of roots to remove the second term. To keep things simple, I have shown the method only for the form ax^3+bx+c=0. Simple algebra and knowledge of complex numbers is the prerequisite. Watch the full video for the solution and don't forget to comment your queries and suggestions.

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I couldn't solve it because i had to find out the cube root of -4+4isqrt(3). Which I don't know how.