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3 years ago

What is the result of subtracting the second equation from the first?

Mathematics

2 answers:

Elina [12.6K]3 years ago

7 0

Answer:

-9

Step-by-step explanation:

The awnswer to the first equation is -4 and -4-5 is equal to -9

tatyana61 [14]3 years ago

6 0

Answer:

90.7 - 8y = -9.

Step-by-step explanation:

87 - 4y = -4

-3.7 + 4y = 5

87 - (-3.7) - 4y - 4y = -4 - 5

90.7 - 8y = -9

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Which of the objects shown above are pyramids?

PolarNik [594]

<h3>Answer: A and B (first answer choice)</h3>

Explanation:

Both figures shown in A and B are triangular pyramids. The base is a triangle, and the lateral sides are also triangles. Another example would be rectangular pyramids where the base is a rectangle, and the lateral sides are triangles.

Choice C is ruled out because cones aren't considered pyramids.

Choice D is a combination of a rectangular prism, and a rectangular pyramid stacked on top, so it's not purely a pyramid only. We can rule out choice D.

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3 years ago

Simplify 4x(3x-7)-19x^2)-19x^2

Sedbober [7]

The answer for this problem is
: -7(x^2+4)

3 0

3 years ago

Joaquin has $1,300 in the bank and has investments worth $4,000. He also has $7,000 worth of credit card debt. What is Joaquin's

svetlana [45]

The answer to this question would be: <span>-$1,700

In this question, we can separate the account into positive/debit and negative/credit value. The positive/debit value should be:

Joaquin has $1,300 in the bank
He has $4,000 worth of investment
Total positive value = $1300 + $4000= $5300

The negative value should be
</span><span>$7,000 worth of credit card debt
</span>Total positive value =$7000
<span>
Then the net worth should be: $5300 - $7000= -$1700</span>

7 0

4 years ago

What’s 2.95 as a percent

hichkok12 [17]

Answer:

295%

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers

A sample of 200 observations from the first population indicated that x1 is 170. A sample of 150 observations from the second po

igor_vitrenko [27]

Answer:

a) For this case the value of the significanceis $\alpha=0.05$ and $\alpha/2 =0.025$ , we need a value on the normal standard distribution thataccumulates 0.025 of the area on each tail and we got:

$z_{\alpha/2} =1.96$

If the calculated statistic $|z_{calc}| >1.96$ we can reject the null hypothesis at 5% of significance

b) Where $\hat p=\frac{X_{1}+X_{2}}{n_{1}+n_{2}}=\frac{170+110}{200+150}=0.8$

c) $z=\frac{0.85-0.733}{\sqrt{0.8(1-0.8)(\frac{1}{200}+\frac{1}{150})}}=2.708$

d) Since the calculated value satisfy this condition 2.708>1.96 we have enough evidence at 5% of significance that we have a significant difference between the two proportions analyzed.

Step-by-step explanation:

Data given and notation

$X_{1}=170$ represent the number of people with the characteristic 1

$X_{2}=110$ represent the number of people with the characteristic 2

$n_{1}=200$ sample 1 selected

$n_{2}=150$ sample 2 selected

$p_{1}=\frac{170}{200}=0.85$ represent the proportion estimated for the sample 1

$p_{2}=\frac{110}{150}=0.733$ represent the proportion estimated for the sample 2

$\hat p$ represent the pooled estimate of p

z would represent the statistic (variable of interest)

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

$\alpha=0.05$ significance level given

Concepts and formulas to use

We need to conduct a hypothesis in order to check if is there is a difference between the two proportions, the system of hypothesis would be:

Null hypothesis: $p_{1} = p_{2}$

Alternative hypothesis: $p_{1} \neq p_{2}$

We need to apply a z test to compare proportions, and the statistic is given by:

$z=\frac{p_{1}-p_{2}}{\sqrt{\hat p (1-\hat p)(\frac{1}{n_{1}}+\frac{1}{n_{2}})}}$ (1)

a.State the decision rule.

For this case the value of the significanceis $\alpha=0.05$ and $\alpha/2 =0.025$ , we need a value on the normal standard distribution thataccumulates 0.025 of the area on each tail and we got:

$z_{\alpha/2} =1.96$

If the calculated statistic $|z_{calc}| >1.96$ we can reject the null hypothesis at 5% of significance

b. Compute the pooled proportion.

Where $\hat p=\frac{X_{1}+X_{2}}{n_{1}+n_{2}}=\frac{170+110}{200+150}=0.8$

c. Compute the value of the test statistic.

z-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

Replacing in formula (1) the values obtained we got this:

$z=\frac{0.85-0.733}{\sqrt{0.8(1-0.8)(\frac{1}{200}+\frac{1}{150})}}=2.708$

d. What is your decision regarding the null hypothesis?

Since the calculated value satisfy this condition 2.708>1.96 we have enough evidence at 5% of significance that we have a significant difference between the two proportions analyzed.

5 0

3 years ago