Answer: Medication in Lexi's system on day t becomes,

Step-by-step explanation:
Since we have given that
Initial amount Sofia takes of a medicine = 10 mg
Concentration in blood decreases by a factor of one half every day.
So, it becomes,

According to question, four days later, it becomes,

We have given that Lexi takes 10 mg of the same medicine.
So, it becomes,

Hence, Medication in Lexi's system on day t becomes,

If the figure is an isosceles trapezoid, then both slanted sides have the same length. 2x+2=4. That gives you 'x', and the line on top is double-x.
I don’t know if you can even read this but make your graph points, rather than 1,2,3,4 etc. Make them 1/4,2/4,3/4,4/4, and 1/2,2/2,3/2,4/3, etc.. at least until you can plot your points. Make the numbers into mixed fractions or improper fractions whatever they call it. Make it to where the top is bigger than the bottom by multiplying the whole number by the denominator.