Maximise `Z=-x+2y`
Subject to the constraints `xge3, x+yge5,x+2yge6,yge0`

Explanation

To solve the linear programming problem of maximizing \( Z = -x + 2y \) subject to the constraints \( x \geq 3 \), \( x + y \geq 5 \), \( x + 2y \geq 6 \), and \( y \geq 0 \), we will follow these steps:

### Step 1: Identify the constraints and convert them into equations
The constraints are:
1. \( x \geq 3 \)
2. \( x + y \geq 5 \)
3. \( x + 2y \geq 6 \)
4. \( y \geq 0 \)
...