Answer:
Simplify
![Q-[R+S]-T](https://img.qammunity.org/2020/formulas/mathematics/middle-school/97rcr8beyfy73rrzb3wtcnjuraaay7psvw.png)
The answer is:

Explanation:
We have the expressions:

Now, we need simplify:
![Q-[R+S]-T](https://img.qammunity.org/2020/formulas/mathematics/middle-school/97rcr8beyfy73rrzb3wtcnjuraaay7psvw.png)
We need to replace each term by the expressions:
![7m+3n-[(11-2m)+(n+5)]-(-m-3n+8)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5ikr6gjzij660zfl5m4tn0as04q4szmwmi.png)
We need to remember the rule of signs:



With this in mind we solve the parentheses:
![7m+3n-[(11-2m)+(n+5)]-(-m-3n+8)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5ikr6gjzij660zfl5m4tn0as04q4szmwmi.png)
![7m+3n-[11-2m+n+5]+m+3n-8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/z8pz3o59r3jxjqfddzzab618j8087w69w7.png)

let's group common terms

We must add and subtract common terms:

The answer is:
