{3 pts.} Convert this general minimization problem to a general maximization problem.
Do not find the solution to this system. Do not set up any tableaux.
Minimize
c = 9x - 2y + w + 3z
Subject to
$\begin{cases}
9x - y + z \le 30 \\
x + y - z + w \ge 290 \\
8x + 8z - 900w \le 39 \\
x > 0, y > 0, z > 0, w \ge 0.
\end{cases}$