Chapter 4.3, Problem 4E

In Exercises 1–4, write each linear programming problem as a maximization problem with all inequalities (except $x\ge 0,y\ge 0,\mathrm{.....}$) written in the form $\left[\text{linear}\text{inequality}\le \text{constant}\right]$.

Maximize $375-2x-3y$ subject to the constraints

$\{\begin{array}{c}x\ge 0,y\ge 0\\ x\le 30,y\le 25\\ x+y\le 45\\ x+y\ge 15.\end{array}$