Answer:
14 hours
Step-by-step explanation:
If you need to take 1 pill every 3.5 hours then this suggest that the effects of 1 pill lasts for 3.5 hours.
Therefore, if you take 4 pills then they will last: 4 x 3.5 = 14 hours
Either you can use distributive property or you can add up the numbers in the brackets.
Hopefully that helped! :)
The formula to find the distance between points

and

is given as

, where

is the vertical distance between two points on the y-axis

is the horizontal distance between two points on the x-axis