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3 years ago

What's the equivalent expression. (2-7. 5)² =?

Mathematics

2 answers:

Brut [27]3 years ago

8 0

Answer:

The Answer of the above question is 30.25

Step-by-step explanation:

Hope it helps you.

Alekssandra [29.7K]3 years ago

3 0

Answer: 30.25

Step 1: Rewrite equation

To start off, I find it helpful to rewrite the equation. This will give you a better understanding of the problem. Let’s do this now.

(2-7.5)²

Step 2: Understand PEMDAS

Now that we have written down the equation, let’s solve using PEMDAS. In case you are unfamiliar, I will write down what each letter stands for. Keep in mind that the letters go in the order you need to solve.

P- Parentheses
E- Exponent
M- Multiplication
D- Division
A- Addition
S- Subtraction

Step 3: Solve

Finally, we can solve the equation. Using the knowledge from step 2, we will be able to solve in the correct order. Let’s start with parentheses, and find the answer for 2-7.5.

(2-7.5)²
-5.5²

Now let’s move on to the next letter and solve using the exponent. We will multiply -5.5 by itself. This will be the final step; although there are other letters in PEMDAS, the equation will end after this step since we will already have the answer.

-5.5²
30.25

Hope this helps! Comment below for more questions.

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A westbound train travels 16 miles per hour slower than the eastbound train. If two trains are 800 miles apart after 5 hours wha

lozanna [386]

Answer:

Step-by-step explanation:

The rate can be calculated as follows

x + x -16

2x-16

(2x-16)×5

10x - 80= 800

10x = 300-80

10x, = 220

x = 220/10

= 22

22-16

= 6 mph

Hence the rate of the west bound tsin is 6mph

7 0

3 years ago

What is the ‘r’ value of the following sequence: 6, 18, 54, 162…?

goblinko [34]

R = 3
6x3=18
18x3=54
54x3=162 ...

5 0

3 years ago

A newspaper poll asked respondents if they trusted "eco friendly" labels on cleaning products. Out of 1000 adults surveyed, 498

Paul [167]

Answer:

So the p value obtained was a very high value and using the significance level assumed $\alpha=0.05$ we have $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the proportion of respondents that trust these labels is not significanlty less than 0.5 or 50%.

Step-by-step explanation:

1) Data given and notation

n=1000 represent the random sample taken

X=498 represent the adults that trust these labels

$\hat p=\frac{498}{1000}=0.498$ estimated proportion of respondents that trust these labels

$p_o=0.5$ is the value that we want to test

$\alpha$ represent the significance level

z would represent the statistic (variable of interest)

$p_v$ represent the p value (variable of interest)

2) Concepts and formulas to use

We need to conduct a hypothesis in order to test the claim that the proportion of respondents that trust these labels is at least 50%:

Null hypothesis: $p\geq 0.5$

Alternative hypothesis: $p < 0.5$

When we conduct a proportion test we need to use the z statisitc, and the is given by:

$z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}$ (1)

The One-Sample Proportion Test is used to assess whether a population proportion $\hat p$ is significantly different from a hypothesized value $p_o$ .

3) Calculate the statistic

Since we have all the info requires we can replace in formula (1) like this:

$z=\frac{0.498 -0.5}{\sqrt{\frac{0.5(1-0.5)}{1000}}}=-0.126$

4) Statistical decision

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.

The significance level is not provided but we can assume it as $\alpha=0.05$ . The next step would be calculate the p value for this test.

Since is a left tailed test the p value would be:

$p_v =P(Z$