Please help me.<br> Please explain.

Simplify. a - {4 b - [ a - (5 b - c ) + 3 c - ( a - b - 9 c )]}

Vlad1618 [11]

The answer to this should be a-8b+13c

a - {4b - [a - (5b - c) + 3c - (a - b - 9c)]}
=a - {4b - [a - 5b + c + 3c - a + b + 9c]}
=a - {4b - [- 4b+ 13c]}
=a - {4b + 4b -13c}
=a - 8b + 13c

Hope this helped :)
Have a great day

7 0

3 years ago

The Late Show with David Leterman is seen by a relatively large percentage of household members who record the show for viewing

Zanzabum

Answer:

a) Null hypothesis: $\mu \leq 40000$

Alternative hypothesis: $\mu > 40000$

b) $t=\frac{41182-40000}{\frac{19990}{\sqrt{1700}}}=2.438$

c) The first step is calculate the degrees of freedom, on this case:

$df=n-1=1700-1=1699$

Since the sample size is large enough we cna use the z distribution as an approximation for the statsitic on this case.

Since is a one right tailed test the p value would be:

$p_v =P(t_{(1699)}>2.438)=0.0074$

d) If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis at 1% of signficance. So we can conclude that the true mean is higher than 40000 at the significance level assumed.

Step-by-step explanation:

Data given and notation

$\bar X=41182$ represent the sample mean

$s=19990$ represent the sample standard deviation

$n=1700$ sample size

$\mu_o =40000$ represent the value that we want to test

$\alpha=0.01$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

Part a: State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the true mean is greater than 40000, the system of hypothesis would be:

Null hypothesis: $\mu \leq 40000$

Alternative hypothesis: $\mu > 40000$

If we analyze the size for the sample is > 30 but we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Part b: Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{41182-40000}{\frac{19990}{\sqrt{1700}}}=2.438$

Part c: P-value

The first step is calculate the degrees of freedom, on this case:

$df=n-1=1700-1=1699$

Since the sample size is large enough we cna use the z distribution as an approximation for the statsitic on this case.

Since is a one right tailed test the p value would be:

$p_v =P(t_{(1699)}>2.438)=0.0074$

Part d: Conclusion

If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis at 1% of signficance. So we can conclude that the true mean is higher than 40000 at the significance level assumed.

3 0

3 years ago

The width of a rectangle is 7 meters greater than its length. If the area of the rectangle is 170 square meters, write the quadr

Lostsunrise [7]

Since x represents the length (in meters), the width, which is 7 meters greater, is x +7. The product of these dimensions is the area (in square meters):
x(x +7) = 170
In standard form, the quadratic is ...
x² +7x -170 = 0

4 0

3 years ago

A right triangle has an area of 98 inches. If the triangle is an isosceles triangle, what are the lengths of the legs of the tri

Anna007 [38]

Answer:49

Step-by-step explanation:

A=ab/2

98=ab/2

98/2=ab

49=ab

5 0

3 years ago

A store finds that the number of shirts sold increases each week. In the first week, only 15 shirts were sold. In the next week,

Pepsi [2]

The explicit rule for the arithmetic sequence is a(n) = 7n + 8 if the arithmetic series is 15, 22, 29,...

<h3>What is a sequence?</h3>

It is defined as the systematic way of representing the data that follows a certain rule of arithmetic.

We have:

In the first week, only 15 shirts were sold. In the next week, 22 shirts were sold and in the third week, 29 shirts were sold.

15, 22, 29,...

The first term a = 15

The common difference d = 22 - 15 = 7

a(n) = 15 + (n - 1)7

a(n) = 7n + 8

Thus, the explicit rule for the arithmetic sequence is a(n) = 7n + 8 if the arithmetic series is 15, 22, 29,...

Learn more about the sequence here:

brainly.com/question/21961097

#SPJ1

6 0

2 years ago

Please help me. Please explain.