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boyakko [2]
3 years ago
10

Factor completely -x^2+3x+28

Mathematics
1 answer:
jarptica [38.1K]3 years ago
6 0
(7 - x)(x + 4) = -x² + 7x - 4x + 28
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HELP!!!!!!!!!!!!!!!!!!!ASAP WILL GIVE BRAINLEST
Assoli18 [71]

not riding a motor cycle given that they read

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5

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3 0
2 years ago
We are conducting a hypothesis test to determine if fewer than 80% of ST 311 Hybrid students complete all modules before class.
Juli2301 [7.4K]

Answer:

z=\frac{0.881 -0.8}{\sqrt{\frac{0.8(1-0.8)}{110}}}=2.124  

Null hypothesis:p\geq 0.8  

Alternative hypothesis:p < 0.8  

Since is a left tailed test the p value would be:  

p_v =P(Z  

So the p value obtained was a very high value and using the significance level assumed \alpha=0.05 we have p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis.

Be Careful with the system of hypothesis!

If we conduct the test with the following hypothesis:

Null hypothesis:p\leq 0.8  

Alternative hypothesis:p > 0.8

p_v =P(Z>2.124)=0.013  

So the p value obtained was a very low value and using the significance level assumed \alpha=0.05 we have p_v so we can conclude that we have enough evidence to reject the null hypothesis.

Step-by-step explanation:

1) Data given and notation  

n=110 represent the random sample taken

X=97 represent the students who completed the modules before class

\hat p=\frac{97}{110}=0.882 estimated proportion of students who completed the modules before class

p_o=0.8 is the value that we want to test

\alpha represent the significance level

z would represent the statistic (variable of interest)

p_v{/tex} represent the p value (variable of interest)  2) Concepts and formulas to use  We need to conduct a hypothesis in order to test the claim that the true proportion is less than 0.8 or 80%:  Null hypothesis:[tex]p\geq 0.8  

Alternative hypothesis:p < 0.8  

When we conduct a proportion test we need to use the z statistic, and the is given by:  

z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}} (1)  

The One-Sample Proportion Test is used to assess whether a population proportion \hat p is significantly different from a hypothesized value p_o.

3) Calculate the statistic  

Since we have all the info requires we can replace in formula (1) like this:  

z=\frac{0.881 -0.8}{\sqrt{\frac{0.8(1-0.8)}{110}}}=2.124  

4) Statistical decision  

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.  

The significance level assumed \alpha=0.05. The next step would be calculate the p value for this test.  

Since is a left tailed test the p value would be:  

p_v =P(Z  

So the p value obtained was a very high value and using the significance level assumed \alpha=0.05 we have p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis.

Be Careful with the system of hypothesis!

If we conduct the test with the following hypothesis:

Null hypothesis:p\leq 0.8  

Alternative hypothesis:p > 0.8

p_v =P(Z>2.124)=0.013  

So the p value obtained was a very low value and using the significance level assumed \alpha=0.05 we have p_v so we can conclude that we have enough evidence to reject the null hypothesis.

5 0
3 years ago
Find the equation of line passing thorugh the point (5,7) and parellel line ,y=5x +4
Savatey [412]
The answer is 0 i hope i helped honey
3 0
3 years ago
Two cars leave at the same time from points A and B, the distance between them is 280 km. If the cars meet each other, they’ll m
kykrilka [37]
Set up the following equations:

2x + 2y = 280

14x - 14y = 280

x represents car A's speed, and y represents car B's speed.

We'll use elimination to solve this system of equations. Multiply the first equation by 7:

(2x + 2y = 280) * 7 = 14x + 14y = 1960

14x - 14y = 280

Combine both equations:

28x = 2240

Divide both sides by 28 to get x by itself:

x = 80

The speed of car A is 80 mph.

Since we now know the value of one of the variables, we can plug it into the first equation:

2(80) + 2y = 280

160 + 2y = 280

Subtract 160 from both sides.

2y = 120

Divide both sides by 2 to get y by itself:

y = 60

The speed of car B is 60 mph.

7 0
3 years ago
I need help can you help me?
Nookie1986 [14]

D - -x^2 + 3x + 7

To find this, first write out the equation:

(3x + 1) - (x^2 - 6)

Distribute the negative into x^2 and -6 so you're equation now looks like this:

3 x + 1 - x^2 + 6

Combine like terms and arrange the equation into ax^2 + bx + c to get the final answer of:

-x^2 + 3x + 7

Hope this helps!

8 0
3 years ago
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