Step-by-step explanation:
Model:
s = slices
x = pizzas ordered
s = .8(.45x) + .12(.55x)
Now plugin 20 for x and you will get the total number of slices.
s = .8(.45x) + .12(.55x)
s = .8(.45(20)) + .12(.55(20))
s = 204 slices
Note, we could make this model different and smaller but I chose this method because it demonstrates what is going on with the word problem
Answer:
8. 
9. 
Step-by-step explanation:

^#8^

^#9^
Answer:
x= 36
Step-by-step explanation:
both angles together are supplementary and will form 180
Therefore, you know the missing angle can be found by substracting 108 from 180
180 - 108 = 72
72 = 2x
Obtuse, it does not fit Pythagoreans for a right triangle, two sides are not equal to be isosceles