解三

反複利用 x^2 = -(5x + 25).

x^3 = -x(5x + 25) = -25x -5x^2 = -25x + 25x + 125 = 125

所有跟帖： 

• 解四 -wxcfan123- ♂ (117 bytes) () 10/16/2022 postreply 19:35:50

• X^3 = 125 -> X=5 -> x^2 + 5x + 25 == 25 + 25 + 25 = 0. -2022_2092- ♂ (0 bytes) () 02/02/2023 postreply 11:10:17