Cubic Polynomials

[Rex.]

I am having a trouble here, anyways to factorise cubic equations?

 

[Nuclear]

https://www.youtube.com/watch?v=Touv2APcBRw

Did not watch the video entirely, but I think this might be what you're looking for. I recommend always searching for Khan Academy videos when you're struggling with a math problem.

khanacademy.org

If you want to learn shit and expand your mind, register there.

Having failed multiple courses of the extended math option at my place of education, I consider myself quite proficient at mathematics.

 

[GhostThruster]

a3 + b3 = (a + b)(a2 - ab + b2)
a3 - b3 = (a - b)(a2 + ab + b2)

 

[PurgeandFire]

For general cubic polynomials with integer coefficients, you'll usually use synthetic division. You'll get all the factors of the leading coefficient and all the factors of the constant term, and then you'll guess-and-check each ratio (plus or minus) in the polynomial.

Pro-tip--a lot of teachers will instruct you to run synthetic division on every term you want to guess, and check if the remainder is 0. That is actually tedious and unnecessary. Just plug in the value you want to guess into the polynomial and see if it evaluates to 0. If you're allowed a calculator, this is really fast compared to doing it by hand. Usually they'll give small roots, so some 1/-1/2/-2 are usually easy to do in your head.

 

[gorillabull]

wolframalpha.com

 

[Nuclear]

WolframAlpha is good if you want solutions instead of learning how to solve. Unless you buy the Pro version which lets you view the step-by-step solution (which I recommend buying, it's pretty cheap for students).