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3 years ago

What is 2 + 2 - 2 + 2

Mathematics

2 answers:

irga5000 [103]3 years ago

5 0

I'm pretty sure it's 4

Anni [7]3 years ago

5 0

Answer:

Step-by-step explanation:

i used my calculator lol

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katovenus [111]

Answer:

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4 0

3 years ago

The length of a rectangle is 8 cm longer than its width. find the dimensions of the rectangle if its area is 108cm

hram777 [196]

Answer:

$4+2\sqrt{31}\text{ by } -4+2\sqrt{31}$

Or about 15.136 centimeters by 7.136 centimeters.

Step-by-step explanation:

Recall that the area of a rectangle is given by:

$\displaystyle A = w\ell$

Where w is the width and l is the length.

We are given that the length is 8 centimeters longer than the width. In other words:

$\ell = w+8$

And we are also given that the total area is 108 square centimeters.

Thus, substitute:

$(108)=w(w+8)$

Solve for w. Distribute:

$w^2+8w=108$

Subtract 108 from both sides:

$w^2+8w-108=0$

Since the equation is not factorable, we can use the quadratic formula:

$\displaystyle x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}$

In this case, a = 1, b = 8, and c = -108. Substitute and evaluate:

$\displaystyle \begin{aligned} w&= \frac{-(8)\pm\sqrt{(8)^2-4(1)(-108)}}{2(1)} \\ \\ &=\frac{-8\pm\sqrt{496}}{2}\\ \\ &=\frac{-8\pm4\sqrt{31}}{2} \\ \\ &=-4 \pm 2\sqrt{31} \end{aligned}$

So, our two solutions are:

$w=-4+2\sqrt{31} \approx 7.136 \text{ or } w=-4-2\sqrt{31}\approx -15.136$

Since width cannot be negative, we can eliminate the second solution.

And since the length is eight centimeters longer than the width, the length is:

$\ell =(-4+2\sqrt{31})+8=4+2\sqrt{31}\approx 15.136$

So, the dimensions of the rectangle are about 15.136 cm by 7.136 cm.

5 0

3 years ago

Which of the following is equavilant to 4x+7y=z

astra-53 [7]

Answer:

Step-by-step explanation:

For this question, you need to get x alone on one side.

$4x+7y=z\\4x=z-7y\\x=\frac{z-7y}{4}$

6 0

3 years ago

Read 2 more answers

PLS HELP WITH MATH HURRY

AlekseyPX

Answer:

x+3=9

Step-by-step explanation:

I hope this helped!

4 0

3 years ago

Read 2 more answers

A food store owner wants to determine the type of products customers prefer to buy. The owner surveyed 40 customers on a day whe

lora16 [44]

There is not a fixed boundary line as to when the sample size should be considered appropriately large but the rule of thumb is a sample size larger than 30 is sufficient enough to assume that the data is normally distributed. Since the sample size in this case is 40, we can consider it appropriately large and use Normal Distribution to deduce the results.

Sample Size = n = 40
Proportion of customer who prefer organic food= p = 40% = 0.40
Confidence Level = 95%
Z score at the confidence Level = z = 1.96

Margin of Error for the population proportion is calculated as:

$M.E=+-z \sqrt{ \frac{p(1-p)}{n} }$

Using the values, we get:

$M.E=+-1.96 \sqrt{ \frac{0.4*0.6}{40} }=+-0.152$

Thus, the option B gives the correct answer.
As the sample size is appropriately large, the margin of error is ±0.152.

6 0

3 years ago