Answer:
![A_w=8x+336](https://img.qammunity.org/2022/formulas/mathematics/high-school/rsq5xxfyh3mwno6lkkuaafob5tv9h6kmgm.png)
Explanation:
From the question we are told that:
Length of pool
![l_p=34](https://img.qammunity.org/2022/formulas/mathematics/high-school/35ilbs5wc3fed1qc3eztax9vomufrbsx5j.png)
width of pool
![w_p=x](https://img.qammunity.org/2022/formulas/mathematics/high-school/ih306l7pr82hmg9bqzp2rer0ayhe053kh3.png)
Width of brick-walk way
Generally the equation for Area of the pool
is mathematically given by
![A_p=l_p*w_p\\\\A_p=34*x](https://img.qammunity.org/2022/formulas/mathematics/high-school/ht4sbm4gcwlvlh2sn5xbych1qaqa5v3sac.png)
Generally the equation for Area of the pool with its walkway
is mathematically given by
![A_w'=l_w'+w_w'\\\\A_w'=l_w'+w_w'](https://img.qammunity.org/2022/formulas/mathematics/high-school/54s7c5ao35jim6eojws5zhlfudjgwd02fi.png)
Where
![l_w'=length\ of\ pool\ with\ walkway\\\\l_w'=l_p+4+4\\\\l_w'=34+4+4\\\\l_w'=42](https://img.qammunity.org/2022/formulas/mathematics/high-school/k9jma1scsjyaxn0kku5mia7e32d7qanmxu.png)
Therefore
![w_w'=width\ of\ pool\ with walkway\\\\w_w'=w_p+8\\\\A_w'=42*(x+8)](https://img.qammunity.org/2022/formulas/mathematics/high-school/lkbvx7jgk4bpbtytj84dka9mlosl3nib0n.png)
Generally the equation for pool's walkway
is mathematically given by
![A_w=A_w'-A_p\\\\A_w=(42*(x+8))-(34x)](https://img.qammunity.org/2022/formulas/mathematics/high-school/t29fmek5i8cckz1n4cvvkzqnqz2me8fzmr.png)
![A_w=8x+336](https://img.qammunity.org/2022/formulas/mathematics/high-school/rsq5xxfyh3mwno6lkkuaafob5tv9h6kmgm.png)