We want to write and solve an algebraic equation to find how many milliliters of medicine a person uses each month.
The solution is 2 ml per month.
We know that in each pen injector we have 0.75mg of active component in 0.5 mL of liquid (written as 0.75mg/0.5 mL).
So, if the person takes 4 of these in a month, then the amount of mass that you get is given by:
x = 4*0.75mg = 3mg of active component per month.
And the volume that the person takes each month is:
y = 4*0.5 mL = 2 mL
Then, answering the question, the person gets 2 mL each month.
If you want to learn more, you can read:
https://brainly.com/question/24758479
