A doctor prescribes a 300-mg antibiotic tablet to be taken every eight hours. Just before each tablet is taken, 20% of the drug remains in the body. (a) How much of the drug is in the body just after the second tablet is taken? After the third tablet?

So after the second  tablet there is 360-mg of drug in the body.

So after the third  tablet there is 372-mg of drug in the body.

Step-by-step explanation:

We know that a  doctor prescribes a 300-mg antibiotic tablet to be taken every eight hours. Just before each tablet is taken, 20% of the drug remains in the body.

We know that  20%=0.2.

We conclude that after the first pill, 300mg of the  drug is in the body.

We have the following formula, to calculate how much mg of the drug is in the body after the second tablet:

So after the second  tablet there is 360-mg of drug in the body.

We have the following formula, to calculate how much mg of the drug is in the body after the third tablet:

So after the third  tablet there is 372-mg of drug in the body.

70,000 + 6,000 + 800 + 30

step-by-step explanation:

(0,-3) see attached graph

step-by-step explanation:

a. to solve the system, graph the two equations.

x = y+3 becomes y=x-3 has m=1/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move up 1 unit and 1 unit to the right. plot a point and connect.

y=-4x+3 has m =-4/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move down four units and to the right 1 unit. plot a point and connect.

the solution is the point (x,y) where the two lines intersect. by the graph below it is (0,-3).

b. to solve by substitution, substitute y = -4x-3 into x= y+3

x= (-4x-3) +3

x=-4x

5x=0

x=0

now substitute x = 0 back in to find y.

y= -4(0)-3

y=0-3

y=-3

solution is (0,-3)

c. use elimination by adding the equations together.

x-y=3

4x+y=-3

5x=0

x=0

then substitute into one equation to find y.

y=-4(0)-3

y=-3