Question

A person dives into a pool from its edge to swim to the other side. The table shows the depth in feet of the person from the surface of the water after x
seconds. The data can be modeled by a quadratic function.
time, x (sec) | depth of person from surface of water, d(x) (feet)
1 | -1.85
4 | -7.28
6 | -8.3
8.5 | -6.65
10 | -4.1
11.5 | -0.38


Which function best models the data?

(1 point)

d(x)=0.05x^2+0.74x


d(x)=0.05x^2+0.74x+9.17


d(x)=0.26x^2−3.11x


d(x)=0.26x^2−3.11x+1

Answer 1

d(x) = 0.26x^2 − 3.11x + 1

(Plugging the given x-values into this function gives the exact depths in the table, e.g. at x=1: 0.26−3.11+1 = −1.85, at x=6: 9.36−18.66+1 = −8.3, etc.)