Question 1099266
81x^4-625
this is a difference of squares
(9x^2+25)(9x^2-25)=0
The second is a difference of squares
(9x^2+25)(3x+5)(3x-5)=0
the real roots are -5/3, +5/3
the complex roots are x^2=-25/9 so x=+/- i (5/3), so -i (5/3),+ i (5/3)
{{{graph(300,300,-10,10,-700,200,81x^4-625)}}}