Answer:
a) cluster sampling
Step-by-step explanation:
In cluster sampling method, each member of a population is assigned to one and only one group.This means clusters are formed through probability method usually a simple random sampling.The participants in the clusters are the only one to be surveyed.
In this example, simple random sampling is used to identify 12 home rooms(cluster) where a group of 20 students (participants) in each room is given the survey.
Answer:
FOIL: 
(3x + 5y)(3x+5y)
F: 3x*3x
O: 3x*5y
I: 5y*3x
L: 5y*5y

Step-by-step explanation:
Answer:
slope is -2/3
Step-by-step explanation:
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