title: how to solve simultaneous equations with solve and with result without roots
body: <p>Here is the code:</p>
  
  <pre><code>syms G1 G2 G3 M1 M2 M3 P1 P2 P3 D1 D2 D3
  S = solve(0 == 0.9 * (20 - G1) - 0.012 * D3 * G1, ...
        0 == 0.9 * (20 - G2) - 0.012 * D1 * G2, ...
        0 == 0.9 * (20 - G3) - 0.012 * D2 * G3, ...
        0 == -0.0033 * M1 + 0.002 * G1, ...
        0 == -0.0033 * M2 + 0.002 * G2, ...
        0 == -0.0033 * M3 + 0.002 * G3, ...
        0 == 0.1 * M1 - 0.0033 * P1 + 2 * 0.5 * D1 - 2 * 0.025 * (P1 ^ 2), ...
        0 == 0.1 * M2 - 0.0033 * P2 + 2 * 0.5 * D2 - 2 * 0.025 * (P2 ^ 2), ...
        0 == 0.1 * M3 - 0.0033 * P3 + 2 * 0.5 * D3 - 2 * 0.025 * (P3 ^ 2), ...
        0 == -0.5 * D1 + 0.025 * (P1 ^ 2) + 0.9 * (20 - G2) - 0.012 * D1 * G2, ...
        0 == -0.5 * D2 + 0.025 * (P2 ^ 2) + 0.9 * (20 - G3) - 0.012 * D2 * G3, ...
        0 == -0.5 * D3 + 0.025 * (P3 ^ 2) + 0.9 * (20 - G1) - 0.012 * D3 * G1)
  </code></pre>
  
  <p>The problem is that I need real solution, but I have got answers with roots. How can I get real answers?</p>