Answer:
[-6,-3]
Explanation:
So we have the compound inequality:
![2x+7\leq x+4\leq 3x+16](https://img.qammunity.org/2021/formulas/mathematics/high-school/vvwvpwq3ut6je8gono4i9apzixptkav7xp.png)
Let's solve for each of the inequalities:
1)
We have:
![2x+7\leq x+4](https://img.qammunity.org/2021/formulas/mathematics/high-school/o1lsrlbhyqy9in0d4dtmojotbizt2cm8hy.png)
Subtract x from both sides:
![x+7\leq 4](https://img.qammunity.org/2021/formulas/mathematics/high-school/nm9wakw683yx6cseeoi6s8sfwujfpx2k08.png)
Subtract 7 from both sides:
![x\leq -3](https://img.qammunity.org/2021/formulas/mathematics/middle-school/7h21ksmp1eq34i5q0msgvbny5rxcf95wae.png)
So that's one of our answers.
2)
We have:
![x+4\leq 3x+16](https://img.qammunity.org/2021/formulas/mathematics/high-school/4uhgfg7wvw43jyyz2j6lzgdfj1nzxd4bki.png)
Subtract 3x from both sides:
![-2x+4\leq 16](https://img.qammunity.org/2021/formulas/mathematics/high-school/e0t5b0rnf2gwt7j5zc73j0q8m5h3f2llw6.png)
Subtract 4 from both sides:
![-2x\leq 12](https://img.qammunity.org/2021/formulas/mathematics/high-school/vuo064uv8yz0rhk8z8pw4a7mgoj2az37jn.png)
Divide both sides by -2. Since we're dividing by a negative, flip the sign:
![x\geq -6](https://img.qammunity.org/2021/formulas/mathematics/middle-school/u178xalw4coi7oghw4oanpj8l09tahje13.png)
Therefore, our entire answer is:
![-6\leq x\leq -3](https://img.qammunity.org/2021/formulas/mathematics/high-school/lz7b8otvqt2afc7uadl5zpgar63opndfdq.png)
This means all values in between -3 and -6 including -3 and -6.
In interval notation, this is:
![[-6,-3]](https://img.qammunity.org/2021/formulas/mathematics/high-school/ffi6ahhki6piy97bzkmb3bdv69iws63tg0.png)
So, A is -6.
And B is -3.
And we're done :)