The expression - 380 + 15y represents a submarine that began at a depth of 380 feet below sea level and ascended at a rate of 15 feet per minute. What was the depth of the submarine after 9
minutes?
Select the correct answer below and, if necessary, fill in the answer box to complete your choice.
OA. The submarine was feet below sea level after 9 minutes.
OB. The submarine will have reached sea level after 9 minutes.
Click to select and enter your answer(s).
Review progress
Question 6
of 50
Back
Next →

The submarine was 245 feet below sea level after 9 minutes.

Step-by-step explanation: Since y represents minutes, replace it with 9...

-380 + 15(9)

-380 + 135

-245

Since it’s negative, the submarine is still below sea level.

step-by-step explanation:

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204