Question 337207
{{{4x^4-16^2+15=0}}}
{{{4x^4-256+15=0}}}
{{{4x^4-241=0}}}
{{{(2x^2+sqrt(241))(2x^2-sqrt(241))=0}}}
{{{x=0 +- root(4,241)/sqrt(2)}}} and 
{{{x=0 +- (root(4,241)/sqrt(2))i}}} where {{{i=sqrt(-1)}}}