What are the roots of #3x^4-28x^3-3x^2+112x-36=0#?

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Answer 1 · 2017-08-03T20:38:26

#3x^4-28x^3-3x^2+112x-36=0#

#3x^4-12x^2-28x^3+112x+9x^2-36=0#

#3x^2*(x^2-4)-28x*(x^2-4)+9*(x^2-4)=0#

#(x^2-4)*(3x^2-28x+9)=0#

#(x+2)* (x-2)* (3x^2-27x+x+9)=0#

#(x+2)* (x-2)* (3x-1)* (x-9)=0#

From these multipliers, roots of it #x=-2#, #x=2#, #x=1/3# and #x=9#.

1) I regrouped terms.

2) I found multipliers

3) I found roots.