Answer:
A.(4,0)
Step-by-step explanation:
APEX
Answer:
Step-by-step explanation:
This is a differential equation problem most easily solved with an exponential decay equation of the form
. We know that the initial amount of salt in the tank is 28 pounds, so
C = 28. Now we just need to find k.
The concentration of salt changes as the pure water flows in and the salt water flows out. So the change in concentration, where y is the concentration of salt in the tank, is
. Thus, the change in the concentration of salt is found in
inflow of salt - outflow of salt
Pure water, what is flowing into the tank, has no salt in it at all; and since we don't know how much salt is leaving (our unknown, basically), the outflow at 3 gal/min is 3 times the amount of salt leaving out of the 400 gallons of salt water at time t:

Therefore,
or just
and in terms of time,

Thus, our equation is
and filling in 16 for the number of minutes in t:
y = 24.834 pounds of salt
Answer:
x - 3
Step-by-step explanation:
We know that the area of a square is length times width.
We also know that a quadratic can be factored:
(x - 3)²
So if each side is (x - 3), then when we do length times width, we get x² - 6x + 9. So our answer is choice D.
In a triangle, the three interior angles always add to 180°
m∠B = 180 - 30 - 80 = 70°
<span>D: 70</span>