Question

The following table shows the number of feet a bird flies above the ground as a function of time:


Time (in seconds)
x Distance above ground (in feet)
f(x)
0 21
2 18
4 15
6 12
8 9


Find and interpret the meaning of the x-intercept in this scenario.
(21, 0); the time it takes for the bird to reach the ground
(14, 0); the time it takes the bird to reach its highest point
(21, 0); the time it takes the bird to reach its highest point
(14, 0); the time it takes for the bird to reach the ground

Answer 1

(21, 0); the time it takes for the bird to reach the ground
am I right?

Answer 2

that's a good guess, but 21 is the height, not the time it takes to reach the ground.

in order to find the x-intercept you have to find the value of x when y = 0, which is not in the table. meaning you have to write the equation

take any two points from the table, let's just use (0,21) and (2,18), write the equation, plug in y = 0 and solve for x

do you need any help with this step?

Answer 3

yes please

Answer 4

slope formula: m = (y2-y1) / (x2-x1)
let (x1,y1) be (0,21) and (x2,y2) be (2,18)

plugging the #'s in: (18-21)/(2-0) ---> evaluate. this becomes your m-value.

once you have m, take one of the two points (let's juse use (0,21)) and plug into y = mx + b to solve for b.

Answer 5

(14, 0); the time it takes the bird to reach its highest point ?

Answer 6

very close, but since the bird is flying downwards---> (14, 0); the time it takes for the bird to reach the ground