Answer:
7/9 = 42/n.
7n = 378,
n = 54.
Step-by-step explanation:
13 cm+ 13 cm= 26 cm, 26 cm is the answer to Part B.
Answer:

Step-by-step explanation:
1) Use the FOIL method: (a+b)(c+d)=ac+ad+bc+bd.

2) Collect like terms.

3) Simplify.

Therefor, the answer is, 10x^3 - 26x^2 - 12x.
Answer: 1.303639
Step-by-step explanation:
The t-score for a level of confidence
is given by :_
, where df is the degree of freedom and
is the significance level.
Given : Level of significance : 
Then , significance level : 
Sample size : 
Then , the degree of freedom for t-distribution: 
Using the normal t-distribution table, we have

Thus, the t-score should be used to find the 80% confidence interval for the population mean =1.303639