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Gala2k [10]
3 years ago
6

Solve using ELIMINATION (with step by step explanation) Please 3x+y=-9 y=5x+7

Mathematics
1 answer:
Yuki888 [10]3 years ago
7 0

Answer:

<h2>x = -2 (verified by algebra) ✅</h2>

Step-by-step explanation:

Since we are given the value of y, we can replace it with 5x + 7.

We now have: 3x + 5x + 7 = -9

We can now simplify by adding 3x and 5x to get 8x.

8x + 7 = -9

We can subtract 7

8x = -16

And now, we divide by 8

x = -2

We can check to make sure we are correct

3(-2) + 5 (-2) + 7 = -9

-6 + -10 + 7 = -9

-9 = -9 ✅

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Building a is 271 meters taller than building
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Let a and b represent the heights of the corresponding buildings (in meters).

... a = b +271 . . . . . . . a is 271 meters taller than b

... 2b -a = 211 . . . . . . if a is subtracted from twice b, the result is 211

Use the expression for a in the first equation to substitute for a in the second.

... 2b - (b+271) = 211

... b = 482 . . . . . . . . . . . simplify and add 271

... a = b +271 = 753

Building a is 753 meters tall; building b is 482 meters tall.

4 0
3 years ago
Suppose a researcher is interested in understanding the variation in the price of store brand milk. A random sample of 36 grocer
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Answer: ($3.055, $3.205)

Step-by-step explanation:

Given : Significance level : \alpha: 1-0.95=0.5

Critical value : z_{\alpha/2}=1.96

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Standard deviation : \sigma= \$\ 0.23

The confidence interval for population mean is given by :_

\overline{x}\pm z_{\alpha/2}\dfrac{\sigma}{\sqrt{n}}

\text{i.e. }\$\ 3.13\pm (1.96)\dfrac{0.23}{\sqrt{36}}\\\\\approx\$\ 3.13\pm0.075\\\\=(\$\ 3.13-0.075,\$\ 3.13+0.075)=(\$\ 3.055,\$\ 3.205)

Hence, the 95% confidence interval to estimate the population mean = ($3.055, $3.205)

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3 years ago
Line t has an equation of y = -8x + 7. Line u includes the point (-1, 7) and is parallel to line
umka2103 [35]

Answer:

y = -8x - 1

Step-by-step explanation:

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7 = 8 + b

-1 = b

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Suppose the high tide in Seattle occurs at 1:00 a.m. and 1:00 p.m. at which time the water is 10 feet above the height of the lo
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Answer:

The low tide, when it is 10 feet below the high tide would be at 7am and 7pm

Step-by-step explanation:

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Answer:

22?

Step-by-step explanation:

Just take 40 and subtract the 7 to get 33 and then 2 to get 31 and 9 to get 22.

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3 years ago
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