-7(-2 ( 3x+1)+ 4) +9

Mathematics

1 answer:

ANTONII [103]2 years ago

7 0

Answer:

correct answer is explained in the picture attached

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What is the solution is to this 3/5(2m-10)=2/3m+10

aivan3 [116]

To find the solution to the given expression, we simply isolate the unknown variable m and perform the necessary operations. The solution is as follows.

(3/5)*(2m-10) = (2/3)*m + 10
15*[(3/5)*(2m-10) = (2/3)*m + 10]
9(2m-10) = 10m + 150
18m-90 =10m + 150
18m - 10m = 150 + 90
8m = 240
m = 240/8
m = 30

First, we multiply the whole expression to the least common denominator (LCD) which is 15. Multiplication and division were then performed accordingly. The terms containing the variable m were transposed to the left side of the equation. Mathematical operations were then applied to get the final value of m which is equal to 30.

8 0

3 years ago

The manager of Petco, a nationwide chain of pet supply stores, wants to study characteristics of the customers, particularly the

shutvik [7]

Answer:

The 95% confidence interval would be given by (19.141;23.538)

Step-by-step explanation:

1) 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".

$\bar X=21.34$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=9.22 represent the sample standard deviation

n=70 represent the sample size

2) Confidence interval

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

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

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=70-1=69$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,69)".And we see that $t_{\alpha/2}=1.994$