Question 1174689

{{{2x^4-7x^2-4= 0}}}

{{{2x^4+x^2-8x^2-4= 0}}}

{{{(2x^4+x^2)-(8x^2+4)= 0}}}

{{{x^2(2x^2+1)-4(2x^2+1)= 0}}}

{{{(x^2-4) (2x^2 + 1) = 0}}}

{{{(x - 2) (x + 2) (2x^2 + 1) = 0}}}


if{{{(x - 2) = 0}}}=> {{{x=2}}}
if 
{{{ (x + 2) = 0}}}=> {{{x=-2}}}

if {{{ (2x^2 + 1) = 0}}}=> {{{ 2x^2 =- 1}}}=> {{{ x^2 =- 1/2}}}=> {{{ x =sqrt(- 1/2)}}}
=> {{{ x =i*sqrt(1/2)}}}or {{{ x =-i*sqrt( 1/2)}}}

=> {{{ x =i/sqrt(2)}}}or {{{ x =-i/sqrt( 2)}}}

real roots:
{{{x=2}}}
{{{x=-2}}}

complex roots:
{{{ x =i/sqrt(2)}}}
{{{ x =-i/sqrt( 2)}}}