4 b - 625
b^4 - 1*625
1*(b + 5)*(b - 5)*(b + 5*I)*(b - 5*I)
(((1*(b + 5))*(b - 5))*(b + 5*i))*(b - 5*i)
-625.0 + b^4
/ 2\ (-5 + b)*(5 + b)*\25 + b /
(-5 + b)*(5 + b)*(25 + b^2)