Answer:
![4x+6y+8z\le 210\\ \\2x+4y+2z\le 150\\ \\2x+2y+4z\le 90\\ \\x\ge 0\\ \\y\ge 0\\ \\z\ge 0](https://img.qammunity.org/2020/formulas/mathematics/high-school/jfqujsfta05xw9rup8wasob73i9tkxmw1m.png)
Explanation:
Let
- x the amount of type A produced;
- y the amount of type B produced;
- z the amount of type C produced.
Cleaning requires 4 minutes for type A, 6 minutes for type B and 8 minutes for type C. In total, 3.5 hours, then
![4x+6y+8z\le 3.5\cdot 60](https://img.qammunity.org/2020/formulas/mathematics/high-school/vot4j0qd29igpvoq8adja7a7u4q94u8hsm.png)
Cutting requires 2 minutes for type A, 4 minutes for type B and 2 minutes for type C. In total, 2.5 hours, then
![2x+4y+2z\le 2.5\cdot 60](https://img.qammunity.org/2020/formulas/mathematics/high-school/mxobsaiu4rc8w275zxs61mjhw2nclgo9li.png)
Packaging requires 2 minutes for type A, 2 minutes for type B and 4 minutes for type C. In total, 1.5 hours, then
![2x+2y+4z\le 1.5\cdot 60](https://img.qammunity.org/2020/formulas/mathematics/high-school/vb26eem2zqfvmc90qd66jdo6bue7hluymv.png)
Note that
![x\ge 0\\y\ge 0\\z\ge 0](https://img.qammunity.org/2020/formulas/mathematics/high-school/ctqh2lt3884zbul03m85wt3mpdu849quxr.png)
Hence, we have 6 inequalities:
![4x+6y+8z\le 210\\ \\2x+4y+2z\le 150\\ \\2x+2y+4z\le 90\\ \\x\ge 0\\ \\y\ge 0\\ \\z\ge 0](https://img.qammunity.org/2020/formulas/mathematics/high-school/jfqujsfta05xw9rup8wasob73i9tkxmw1m.png)