Question 462976
{{{x^4+2x^3+x^2-4 = x^3(x+2) + (x-2)(x+2) = (x^3 + x - 2)(x+2) = (x^2 + x + 2)(x-1)(x+2) = 0}}}

==> The real roots of f(x) are 1, -2.