Answer:
![-3(1)/(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/dw2iglej137vx6mjn2p0nwmqihutn56rpp.png)
Explanation:
Since, after decreasing the water level by 2 feet,
Changes in water level = -2 feet,
Again after decreasing the water level by
feet,
Changes in water level =
feet,
Thus, the total change in water level =
![-2-1(1)/(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/yrd11i3p1mlmidw0r8fbqfu3oio36geu4n.png)
![=-2-1-(1)/(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ktozy3wd88rx3u4ff7akhspl0imvngks5v.png)
![=-3-(1)/(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/t2rtap8ytjff5ktbibvf3a4z0anayx6389.png)
![=-(3+(1)/(3))](https://img.qammunity.org/2020/formulas/mathematics/middle-school/1lkg6um3vewxk2j64geq8n80lbbetoslx8.png)
![=-3(1)/(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5k4pz0fs2ef6s1wjc64ld9u6a53jweaof2.png)
Which is the required expression.