Question 486443
{{{x^4 - 2x^2 + 1}}}
Use formula {{{a^2-2ab+b^2=(a-b)^2}}}
{{{x^4 - 2x^2 + 1=(x^2)^2-2*x^2*1+1^2=(x^2-1)^2}}}
for {{{x=-4}}}
{{{((-4)^2-1)^2=(16-1)^2=15^2=225}}}