A dosage is changed from 15 mg per day to 12 mh per day. what is a percentage decrease

20%

Step-by-step explanation:

dosage change from 15 mg/d to 12 mg/d

change= 15-12= 3

change %= 3/15*100%= 20% decrease

The first thing we must do for this case is to find the equation of the line for CD.
 We have then:
 
 Where,
 
 Substituting values:
 
 We choose an ordered pair:
 
 Substituting values:
 
 Rewriting:
 
 Then, we look for the equation of the line perpendicular to CD.
 We have an equation of the form:
 
 As the lines are perpendicular:
 
 Then, as the line passes through the point (-1, 6) then substituting, we can find the value of b:
 
 Then, the equation of the line is:
 
 
 b. y = -0.5x + 5.5