x^4-9x^2-4x+12 == x^2(x^2-9)-4(x-3) == x^2(x-3)(x+3)-4(x-3) == this can be further factored/simplified but im not sure how to continue?

Question

x^4-9x^2-4x+12 ==> x^2(x^2-9)-4(x-3) ==> x^2(x-3)(x+3)-4(x-3) ==> this can be further factored/simplified but im not sure how to continue?

lucaz · Answer

factor out the x-3 ?  I think its the only thing you can do

briensmarandache · Answer

so i get (x-3)[x^2(x+3)-4] but i know it can be simplified further. the answer i saw in class looked like this (a+/-b) (a+/-b) (a+/-b)^2

lucaz · Answer

you can use polynomial division to find a factored form, but I dont know if thats the idea of the exercise

lucaz · Answer

the website wolframalpha says shows this alternate form:
(x-3)(x-1)(x+2)^2

triciaal · Answer

I didn't get to that but 
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