盛金公式 - 一元三次方程求解 a,b,c,d 一元三次方程的系数…… ax^3+bx^2+cx+d=0 适用这样的方程 说明：源码里去掉了虚根，经检测，程序计算结果正确-Sheng Jin formula- a three order equation solving A, B, C, factor D yuan three equations...... Ax^3+bx^2+cx+d=0 applies to such equations Note: the sour