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dedylja [7]
3 years ago
14

-4.2x=21 what does x mean PLEASE

Mathematics
2 answers:
Ad libitum [116K]3 years ago
7 0

Answer:

X is a variable or a symbol for a number we don't know yet. The variable can be plugged in with any number (a fraction, decimal, etc,). For X, the answer would be 5.


zhenek [66]3 years ago
4 0
X is a number that we don’t know yet
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Christy and Becky went apple picking.Christy picked 1/4 the amount of apples that Becky picked.If Becky picked 124 apples.how ma
Stels [109]

Answer:

31

Step-by-step explanation:

1/4 of 124, ¨of¨¨ represents multiplication

so 1/4*124=124/4

which 124 divided by 4 equals 31

5 0
3 years ago
triangle ABC above is isosceles with AB=AC and BC =48. the ratio of DE is 5:7. what is the length of DC
marshall27 [118]

Answer:

28

Step-by-step explanation:

Question Image is attached.

Triangle BED and Triangle CFD are similar.

We can let the length of BD be 5x and DC 7x

We also know BC = 48, thus we can write:

5x + 7x = 48

12x = 48

x = 4

Now, Since DC = 7x, we plug in x = 4 into it.

DC = 7x

DC = 7(4)

DC = 28

Length of DC is 28

6 0
3 years ago
Read 2 more answers
Toll Brothers is a luxury home builder that would like to test the hypothesis that the average size of new homes exceeds 2,400 s
boyakko [2]

Answer:

Since the pvalue of the test is 0.09 > 0.01, we do not reject the null hypothesis that the average size of new homes is of 2400 square feet.

Step-by-step explanation:

Toll Brothers is a luxury home builder that would like to test the hypothesis that the average size of new homes exceeds 2,400 square feet. Test to see if the average size of new homes exceeds 2,400 square feet.

At the null hypothesis, we test if the average is of 2400 square feet, that is:

H_o: \mu = 2400

At the alternate hypothesis, we test if the average is greater than 2400 square feet, that is:

H_a: \mu > 2400

The test statistic is:

Since we have the standard deviation for the sample, we use the t-distribution.

t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}

In which X is the sample mean, \mu is the value tested at the null hypothesis, s is the standard deviation of the sample and n is the size of the sample.

2400 is tested at the null hypothesis:

This means that \mu = 2400

A random sample of 36 newly constructed homes had an average of 2,510 square feet with a sample standard deviation of 480 square feet.

This means that n = 36, X = 2510, s = 480

Test statistic:

t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}

t = \frac{2510 - 2400}{\frac{480}{\sqrt{36}}}

t = 1.375

Pvalue of the test and decision:

The pvalue of the test is the probability of finding a sample mean of at least 2510, which is the pvalue of t = 1.375 with 36 - 1 = 35 degrees of freedom, using a one-tailed test.

With the help of a calculator, this pvalue is of 0.09

Since the pvalue of the test is 0.09 > 0.01, we do not reject the null hypothesis that the average size of new homes is of 2400 square feet.

6 0
2 years ago
(2x-3)^2=49<br><img src="https://tex.z-dn.net/?f=%282x%20-%203%20%29%20%5E%7B2%7D%20%3D%2049" id="TexFormula1" title="(2x - 3 )
inna [77]
(2x-3)^2=49\iff2x-3=\pm\sqrt{49}\\\\2x-3=-7\ \vee\ 2x-3=7\ \ \ |+3\\\\2x=-4\ \vee\ 2x=10\ \ \ \ |:2\\\\x=-2\ \vee\ x=5
5 0
3 years ago
What is .00000786 in scientific notation
Bas_tet [7]

Sorry that I don't have the answer. Hope this helps!

Remember that any whole number can be written with a decimal point. For example: 2,890,000,000 = 2,890,000,000.0

Now, move the decimal place until you have a number between 1 and 10. If you keep moving the decimal point to the left in 2,890,000,000 you will get 2.89.

Next, count how many places you moved the decimal point. You had to move it 9 places to the left to change 2,890,000,000 to 2.89. You can show that you moved it 9 places to the left by noting that the number should be multiplied by 109

5 0
3 years ago
Read 2 more answers
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