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tester [92]
3 years ago
10

Which expression is equivalent to -2 - 7 -2 - (-7) 2 - 7 -2 + (-7) 2+7

Mathematics
2 answers:
andrew11 [14]3 years ago
8 0

Answer:

-2+ (-7) = -2 - 7

Step-by-step explanation:

Lunna [17]3 years ago
7 0

Answer:

Step-by-step explanation:

-2+ (-7) = -2 - 7

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Did he watch the whole movie
valentinak56 [21]
No, he has not watched the whole movie. The answer would be D. he only has 2/15 to watch. 

Hope I helped!
8 0
3 years ago
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Solve the system by elimination.(show your work)
PilotLPTM [1.2K]

Answer:

x = 1 , y = 1 , z = 0

Step-by-step explanation by elimination:

Solve the following system:

{-2 x + 2 y + 3 z = 0 | (equation 1)

-2 x - y + z = -3 | (equation 2)

2 x + 3 y + 3 z = 5 | (equation 3)

Subtract equation 1 from equation 2:

{-(2 x) + 2 y + 3 z = 0 | (equation 1)

0 x - 3 y - 2 z = -3 | (equation 2)

2 x + 3 y + 3 z = 5 | (equation 3)

Multiply equation 2 by -1:

{-(2 x) + 2 y + 3 z = 0 | (equation 1)

0 x+3 y + 2 z = 3 | (equation 2)

2 x + 3 y + 3 z = 5 | (equation 3)

Add equation 1 to equation 3:

{-(2 x) + 2 y + 3 z = 0 | (equation 1)

0 x+3 y + 2 z = 3 | (equation 2)

0 x+5 y + 6 z = 5 | (equation 3)

Swap equation 2 with equation 3:

{-(2 x) + 2 y + 3 z = 0 | (equation 1)

0 x+5 y + 6 z = 5 | (equation 2)

0 x+3 y + 2 z = 3 | (equation 3)

Subtract 3/5 × (equation 2) from equation 3:

{-(2 x) + 2 y + 3 z = 0 | (equation 1)

0 x+5 y + 6 z = 5 | (equation 2)

0 x+0 y - (8 z)/5 = 0 | (equation 3)

Multiply equation 3 by 5/8:

{-(2 x) + 2 y + 3 z = 0 | (equation 1)

0 x+5 y + 6 z = 5 | (equation 2)

0 x+0 y - z = 0 | (equation 3)

Multiply equation 3 by -1:

{-(2 x) + 2 y + 3 z = 0 | (equation 1)

0 x+5 y + 6 z = 5 | (equation 2)

0 x+0 y+z = 0 | (equation 3)

Subtract 6 × (equation 3) from equation 2:

{-(2 x) + 2 y + 3 z = 0 | (equation 1)

0 x+5 y+0 z = 5 | (equation 2)

0 x+0 y+z = 0 | (equation 3)

Divide equation 2 by 5:

{-(2 x) + 2 y + 3 z = 0 | (equation 1)

0 x+y+0 z = 1 | (equation 2)

0 x+0 y+z = 0 | (equation 3)

Subtract 2 × (equation 2) from equation 1:

{-(2 x) + 0 y+3 z = -2 | (equation 1)

0 x+y+0 z = 1 | (equation 2)

0 x+0 y+z = 0 | (equation 3)

Subtract 3 × (equation 3) from equation 1:

{-(2 x)+0 y+0 z = -2 | (equation 1)

0 x+y+0 z = 1 | (equation 2)

0 x+0 y+z = 0 | (equation 3)

Divide equation 1 by -2:

{x+0 y+0 z = 1 | (equation 1)

0 x+y+0 z = 1 | (equation 2)

0 x+0 y+z = 0 | (equation 3)

Collect results:

Answer: {x = 1 , y = 1 , z = 0

6 0
2 years ago
Read 2 more answers
A random sample of size n1= 25, taken from a normal population with a standard deviation σ1= 5, has a mean X1= 80. A second rand
sesenic [268]

Answer:

The 94% confidence interval would be given by 2.898 \leq \mu_1 -\mu_2 \leq 7.102

Step-by-step explanation:

Previous concepts  

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".  

The margin of error is the range of values below and above the sample statistic in a confidence interval.  

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".  

\bar X_1 =80 represent the sample mean 1

\bar X_2 =75 represent the sample mean 2

n1=25 represent the sample 1 size  

n2=36 represent the sample 2 size  

\sigma_1 =5 sample standard deviation for sample 1

\sigma_2 =3 sample standard deviation for sample 2

\mu_1 -\mu_2 parameter of interest.

The confidence interval for the difference of means is given by the following formula:  

(\bar X_1 -\bar X_2) \pm z_{\alpha/2}\sqrt{\frac{\sigma^2_1}{n_1}+\frac{\sigma^2_2}{n_2}} (1)  

The point of estimate for \mu_1 -\mu_2 is just given by:

\bar X_1 -\bar X_2 =80-75=5

Since the Confidence is 0.94 or 94%, the value of \alpha=0.06 and \alpha/2 =0.03, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.03,0,1)".And we see that z_{\alpha/2}=1.88  

The standard error is given by the following formula:

SE=\sqrt{\frac{\sigma^2_1}{n_1}+\frac{\sigma^2_2}{n_2}}

And replacing we have:

SE=\sqrt{\frac{5^2}{25}+\frac{3^2}{36}}=1.118

Confidence interval

Now we have everything in order to replace into formula (1):  

5-1.88\sqrt{\frac{5^2}{25}+\frac{3^2}{36}}=2.898  

5+1.8\sqrt{\frac{6^2}{36}+\frac{7^}{49}}=7.102  

So on this case the 94% confidence interval would be given by 2.898 \leq \mu_1 -\mu_2 \leq 7.102  

7 0
3 years ago
Peter took one of his friends out to lunch. The lunches cost $100 plus he
77julia77 [94]

Answer:

Tax = $12 Tip = $18 Total Cost = $130

Step-by-step explanation:

tax = tax percentage x amount

0.12 x 100 = 12

tip = tip percentage x amount

0.18 x 100 = 18

The Total Cost

total cost = cost + tax + tip

100 + 12 + 18

Add them up and it would be

$130

5 0
3 years ago
Luke earned a salary of 48,048 last year. how much did he earn per month?
viktelen [127]
$4004 just take 48048 and divide that by 12 to get your answer
5 0
3 years ago
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