If 2,5,7,–4 are the roots of ax⁴ + bx³ + cx² + dx + e = 0 then the roots of ax⁴ – bx³ + cx² – dx + e = 0 are

The roots of f(–x) = 0
  are equal in magnitude but opposite in sign to the roots of f(x)=0

 Given that 2,5,7,–4 are the roots of f(x) =ax⁴ + bx³ + cx² + dx + e = 0 

So -2,-5,-7,4 are  the roots of ax⁴ – bx³ + cx² – dx + e = 0