中文说明：
matlab的基本实现函数有图 例如求代数方程3x5+4x4+7x3+2x2+9x+12=0的所有根。（利用roots函数）
English Description：
The basic implementation functions of MATLAB have legends, such as finding all roots of the algebraic equation 3x5 + 4x4 + 7X3 + 2x2 + 9x + 12 = 0. (using the roots function)