Question

Find all roots x^5-2x^3-8x=0

Answer 1

x^5 - 2 x^3 - 8 x=0x (x - 2) (x + 2) (x^2 + 2) = 0
x - 2 = 0 or x = 0 or x + 2 = 0 or x^2 + 2 = 0
x = 2 or x = 0 or x = - 2 or x^2 = - 2
x^2 = - 2 has no solution since for all x on the real line, x^2 >= 0 and - 2 < 0

Ans : x = 2 or x = 0 or x = - 2