Answer:
5x(−7yz+4y+3)
Step-by-step explanation:
Hmmmmm... I don’t really know I’m so sorry I couldn’t help :(( good luck though!
Answer:
Standard error
Step-by-step explanation:
The standard deviation of the distribution of sample means is called the standard error of the means.
It is denoted by: 
The standard error is calculated using the formula: 
where n is the sample size and
is the population standard deviation.
Answer:
-7/3
Step-by-step explanation:
Answer:
1120 combinations of four teachers include exactly one of either Mrs. Vera or Mr. Jan.
Step-by-step explanation:
The order in which the teachers are chosen is not important, which means that the combinations formula is used to solve this question.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.
In this question:
1 from a set of 2(Either Mrs. Vera or Mr. Jan).
3 from a set of 18 - 2 = 16. So

1120 combinations of four teachers include exactly one of either Mrs. Vera or Mr. Jan.