Answer:
a) 
b) 
Step-by-step explanation:
From the question we are told that:
3 coin are tossed
Therefore
Sample space 
Generally the sets that correspond with the result of at most one tail is therefore given as follows

Therefore
The result is at most one tail when

Answer:
B.
Step-by-step explanation:
So you have to find the base of the trapezoid.
12 + 6 + 2 = 20

Answer:
point of intercept
Step-by-step explanation:
measure x and y axis to see where they cross
4x-2=18
-2 on both sides
4x=16
divid by 4 on both sides
x= 4