Question 92533
square of 3X^3-27X


This can be written as: 


{{{(3x^3 - 27x)^2}}} 


For the above expression to be valid and defined on real numbers we equate it to zero. 


{{{(3x^3 - 27x)^2}}} = 0 


{{{(3x^3 - 27x)}}} = 0 


==> {{{(3x^3) = 27x}}} 


==> {{{(3x^2) = 27}}}  one x term gets calcelled out 



==> {{{x^2 = (27/3)}}}



==> {{{x^2 = 9}}} 


==> Squaring both sides, we get:  


{{{x = + - 9}}}


thus the solution


Regards