Question

A submarine is currently 100-feet below sea level. The function

D(x) = 2x² - 10x - 100 models the depth below sea level, D, in feet, of the
submarine after a minutes have passed.

How Many Feet Below sea level was The submarine At 4 minutes ?

Answer 1

-108 feet

Explanation:

D(x) will tell us the depth of the sub at time x minutes. x = 4 minutes.

D(x) = 2x^2 - 10x - 100

D(4) = 2(4)^2 - 10*(4) - 100 for x=4 minutes

D(4) = 2*16 - 40 - 100

D(4) = 32 -40 - 100

-108 feet