Which equation is a point slope form equation for line ab ?

a) y+1=−3/2(x−1)

b) y+1=3/2(x−1)

A

Step-by-step explanation:

the the slope is negative slope not a positive slope

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