Which function is represented by the graph?
f(x) = {* - 3, x<
13,
x > 0
3, xco
13, x> 0
o f(x) = { x + 3, x 50
1
x > 0
f(x) = \ -* - 3, x < 0
13,
xo

In the area that she observed, the water level fell 13.64mm over 6.4 years, for an average annual rate of change of:
-13.64 ÷ 6.2 = -2.2 mm/ year. 

The difference between how much average water levels rose and how much water levels in her part of the river fell is:
1.8 -(-2.2) = 4 mm/year

During the 6.2 year period: 
4 mm/year * 6.2 = 24.8 mm