25 x^4+10 x = 0
Factor x and constant terms from the left hand side:
5 x (5 x^3+2) = 0
Divide both sides by 5:
x (5 x^3+2) = 0
Split into two equations:
x = 0 or 5 x^3+2 = 0
Subtract 2 from both sides:
x = 0 or 5 x^3 = -2
Divide both sides by 5:
x = 0 or x^3 = -2/5
Taking cube roots gives (-2/5)^(1/3) times the third roots of unity:
Answer: |x = 0 or x = (-2/5)^(1/3) or x = -(2/5)^(1/3) or x = -(-1)^(2/3) (2/5)^(1/3)
