Question 347910
Hi,

.
{{{x^4 - 16*x^2 =0}}}
.
factor
{{{x^2(x^2-16) = 0}}}
.
solve
{{{x^2=0}}}
x=0
{{{x^2-16) = 0}}}
{{{x = root(2,16)}}}
x = +- 4 
.
Solutions: -4, 0, 4