兩邊同乘x x^3 + 5x^2 + 25X = 0.
x^3 + 5(x^2 + 5x) = 0.
兩邊同加125.
125 = x^3 + 5(x^2 + 5x + 25) = x^3
• 解三 -wxcfan123- ♂ (105 bytes) () 10/16/2022 postreply 11:54:43
• 解四 -wxcfan123- ♂ (117 bytes) () 10/16/2022 postreply 19:35:50