符号方程求解器，保存符号方程

Question

  

可能重复：
  Saving a symbolic equation for later use?

从here开始，我正试图解决像这样的符号系统方法

syms x y z;
[x, y, z] = solve('z = 4*x', 'x = y', 'z = x^2 + y^2')
x =
0
2

y =
0
2

z =
0
8

除了我的方程是在m文件中的不同点和随机系数生成的。我的问题是如何才能完成以下任务......

// Generate the first equation.
n = *random number generated here*;
E1 = (z == n*x + 2*n);   // <--- How to save this symbolic equation to use in "solve(...)" later?

// Other work, generate other eqs.
...

// Solve system of eqs.
[x, y, z] = solve( E1 , E2, E3)   // What/How to call/use the previously saved symbolic equations.

感谢您的帮助！