Answer:
w=12
l=20
Explanation:
The area can be found using the following equation:
![A=lw](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6ha4hehcoeuii45f92n9qa4p9h4g0r5n0e.png)
Given the information provided, we are also told the following:
![l=w+8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ferzfw6aov0yl33dwwy3jh58ov78f392av.png)
Therefore, we can plug in our length and our area:
![240=w(w+8)\\240=w^2+8w\\\\w^2+8w-240=0](https://img.qammunity.org/2020/formulas/mathematics/middle-school/wmial96oau2ibs5dt84l644x89quav8gow.png)
We can solve by using the quadratic formula.
![w=(-8+√(8^2-4(1)(-240)) )/(2(1))=12 \\\\](https://img.qammunity.org/2020/formulas/mathematics/middle-school/q50ntdun5jyetbb3x6fhlzivr065hkgxsq.png)
w=12, so w+8=20.