This answer is pretty simple. you see (5,-8) and (20,y). well the 20 is 4 times the 5 on the x value so multiply the y value by 4 to get your answer which Y=-32 in the 2nd corrdenants.
Given that a certain antihistamine is often prescribed for allergies.
And typical dose for 100-pound person is 25 mg every 6 hours.
a) Let us calculate dose per 1 hour for 100-pound person= 
Since 1 week means 7X24= 168 hours, dosage per 1 week = dosage per 168 hours

The number of 12.8 chew able tablets would be taken in a week= 
Hence number of 12.8mg chew able tablets would be taken in a week is 55.
b) Now we can use earlier answer for this problem, since 12.8mg tablet is replaced with 9ml liquid, 55 bottles of 9ml liquid are to be taken in a week.
Hence amount of liquid histamine should a 100-pound person take in a week = 55X9
=495ml
Just divide the y numbers by the x numbers and that's it
Answer:
a. $5.5 b. $19.5
Step-by-step explanation:
t(x)=3.5x+2
x = amount of games
a. t(1)=3.5(1)+2
t(1)=3.5+2
t(1)=5.5
b. t(5)=3.5(5)+2
t(5)=17.5+2
t(5)=19.5
6x=7-4y
Move 'y' to one side
6x-7=-4y
6x-7
------- = y
-4