Answer:
t = 4
Step-by-step explanation:
you have -8 and twelve you equation is x -12 = -8 so we just have to flip the equation around to make it x = 12 -8 which is easy . You just have to make sure you don't get mixed up while flipping the signs.
Answer:
B. 
Step-by-step explanation:
Simplify the expression. Remember to go by the order of operations, or PEMDAS.
1) First, distribute the numbers outside of the set of parentheses to the terms inside the set of parentheses next to them. Then, simplify the fractions.



2) Finally, combine like terms. (This means to add or subtract constants and to add or subtract terms with the same variables.) You may need to convert terms to the same denominator in order to do so easier. Then, reduce the fraction.

Thus, the answer is
.
7,200 = (24)(20)h
15=h (just divide)
To check, 20*24*15 = 7,200 cubic centimeters so 15 cm is right
True, this is a Pythagorean identity.
Answer:
The 90% confidence interval for the true mean lifespan of this product is between 13.1 and 16.9 years.
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 50 - 1 = 49
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 49 degrees of freedom(y-axis) and a confidence level of
. So we have T = 1.6766
The margin of error is:

In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 15 - 1.9 = 13.1 years
The upper end of the interval is the sample mean added to M. So it is 15 + 1.9 = 16.9 years
The 90% confidence interval for the true mean lifespan of this product is between 13.1 and 16.9 years.