SOLUTION: The path of a breaching ocra whale can be modeled by the function k(x) = x^2 - 2x - 8, where x is the time elapsed in seconds under water, and k(x) is the height in ft below the wa

Question 1182040: The path of a breaching ocra whale can be modeled by the function k(x) = x^2 - 2x - 8, where x is the time elapsed in seconds under water, and k(x) is the height in ft below the water.
Determine HOW LONG is the ocra (killer) whale underwater to the nearest second.
Work needs to be shown for me to get the mark
Found 2 solutions by htmentor, ikleyn:
Answer by htmentor(1343)   (Show Source): You can put this solution on YOUR website!
We need to solve for the time, x, when the height k(x) goes to zero
x^2 - 2x - 8 = 0
This can be factored as (x-4)(x+2) = 0 which has solutions x=4, x=-2
Since the elapsed time can't be negative, we take the positive solution, x=4
Thus, the whale spends the time from x=0 to x=4 seconds under water.
Ans: 4 s

Answer by ikleyn(52778)   (Show Source): You can put this solution on YOUR website!
.

        " . . . the height below the water" is called "the depth" in English . . .

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