All categories

2 years ago

Find the value of y when x equals -1. 8x - 2y =10

Mathematics

1 answer:

Artyom0805 [142]2 years ago

6 0

Answer:

y = - 9

Step-by-step explanation:

Substitute in -1 for x

8(-1) - 2y = 10

-8 - 2y = 10

Subtract -8 from both sides

-8 - (-8) cancels out to 0

10 - (-8) = 18

We are left with:

-2y = 18

Divide by -2 on both sides.

-2y/-2 = y

18/-2 = -9

y = -9

You might be interested in

Geometry math question no Guessing and Please show work

Mars2501 [29]

Sum of internal angles on same side of transversal =180

8x-14 +2x+54=180

combining like terms

10x=180-40

x=140/10 =14

so x=14 option D

3 0

3 years ago

The National Institute of Standards and Technology (NIST) supplies "standard materials" whose physical properties are supposed t

Lady bird [3.3K]

Answer:

$10.08-1.64\frac{0.1}{\sqrt{6}}=10.013$

$10.08+1.64\frac{0.1}{\sqrt{6}}=10.147$

So on this case the 90% confidence interval would be given by (10.013;10.147)

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".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma =0.1$ represent the population standard deviation

n represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

In order to calculate the mean and the sample deviation we can use the following formulas:

$\bar X= \sum_{i=1}^n \frac{x_i}{n}$ (2)

$s=\sqrt{\frac{\sum_{i=1}^n (x_i-\bar X)}{n-1}}$ (3)

The mean calculated for this case is $\bar X=10.08$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a tabel to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$