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Art [367]
3 years ago
15

X and y is the variable 4x-7y=3 x-7y=-15 what is the answer please

Mathematics
1 answer:
andrezito [222]3 years ago
6 0
Use linear combination to solve this. It is much faster than substitution. I would start by multiplying the bottom equation by -1.
<span>4x-7y=3
-x+7y=15</span>
Then, add the two equations together. The result is:
3x=18.
You've eliminated one variable. Now you can solve for the other one.
Divide both sides by 3 to get
x=6
Plug this into one of the original equations, then solve for y
-(6)+7y=15
7y=21
y=3

Check your work by plugging these values into both equations to see if they remain true

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Assume that the following confidence interval for the difference in the mean length of male​ (sample 1) and female babies​ (samp
Maksim231197 [3]

Answer:

c. There is no difference in the length between male and female babies

Step-by-step explanation:

Hello!

If I understood correctly, the interval [-0.2;1.7] was constructed to estimate the difference between the population mean of the length of male babies at birth(μ₁) and the population mean of the length of female babies at birth (μ₂).

Estimated parameter: μ₁-μ₂

To make a desition using an interval your hypothesis must be two-tailed,

H₀: μ₁-μ₂ = 0

H₁: μ₁-μ₂ ≠ 0

The level of significance should be complementary to the confidence level of the interval. (For example, if the interval was constructed at 1 - α: 0.9, the test should have a level of α: 0.10)

Remember the Confidence interval is an estimation of the real value of μ₁-μ₂, so, under the null hypothesis you can say that:

If the interval contains the 0, then you don't reject the null hypothesis.

If the interval doesn't contain the 0, you reject the null hypothesis.

So since 0 is contained in the confidence interval, you support the null hypothesis, in other words, there is enough information to say that there is no difference between the average length of male and female babies at birth.

I hope it helps!

5 0
2 years ago
Two ships sail between New York and London. One makes the round trip in 12 days. The other takes 16 days. They both leave London
Mariana [72]
In order to find the answer to this question, you would need to find the Greatest Common Factor of 16 and 12 which would be 4 because 4 is the greatest amount that you can divide both 12 and 16 by. So the soonest both ships will leave together again will be in 4 days.
6 0
3 years ago
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What is 13 x 7? Show your work!
Olin [163]

Answer:

91

Step-by-step explanation:

This is the answer, I took a pic of the work

8 0
2 years ago
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The fourth term of an arithmetic
yulyashka [42]

Answer:

2

Step-by-step explanation:

<u>Given AP where:</u>

  • a₄ = 2a₂ - 1
  • a₆ = 7

<u>To find</u>

  • a₁ = ?

<u>Since</u>

  • a₄ = a₁ + 3d
  • a₂ = a₁ + d
  • a₆ = a₁ + 5d

<u>Initial equations will change as:</u>

  • a₁ + 3d = 2(a₁ + d) - 1  ⇒  a₁ + 3d = 2a₁ + 2d - 1 ⇒ a₁ = d + 1
  • a₁ + 5d = 7 ⇒ a₁ = 7 - 5d

<u>Comparing the above:</u>

  • d + 1 = 7 - 5d
  • 6d = 6
  • d = 1

<u>Then:</u>

  • a₁ = d + 1 = 1 + 1 = 2
  • a₁ = 2

The first term is 2

5 0
3 years ago
What is the measure of the indicated angle?<br> A 180°<br> B 110°<br> C 70°<br> D 90°
ikadub [295]

Answer:

D. 70°

Step-by-step explanation:

the sum of the unknown angle and 110° is 180 °

so, let the unknown angle be x

x+110 = 180

x = 180-110

x = 70°

8 0
2 years ago
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