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2 years ago

What is the value of x

Mathematics

2 answers:

harkovskaia [24]2 years ago

7 0

Answer: x=37.8, you can solve by writing a proportion

Basile [38]2 years ago

7 0

Answer:

x = 37.8

31.5/15=2.1

2.1 x 18=37.8

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Steve made a sign for his room that is shaped like a triangle. It is 4.5 feet long and 3 feet high. He wants to make another sig

Fed [463]

Answer: PART A : $\frac{4.4}{x}$ = $\frac{3}{4}$

PART B : 5.9 FEET

Step-by-step explanation:

Length of the first sign = 4.4 feet

height of the first sign = 3 feet

Length of the second sign = x feet

height of the second sign = 4 feet

If two shapes are similar , then the ratio of their sides are equal,

That is ;

$\frac{h_{1}}{h_{2} }$ = $\frac{L_{1}}{L_{2} }$

PART A

$\frac{4.4}{x}$ = $\frac{3}{4}$

PART B

$\frac{4.4}{x}$ = $\frac{3}{4}$

cross multiplying , we have

3x = 4.4 x 4

3x = 17.6

Divide through by 3

x = 17.6/3

x = 5.86666666666667

x≈ 5.9 feet

Therefore , the length of the new sign is 5.9 feet

6 0

2 years ago

Type the correct answer in each box. Use numerals instead of words. If necessary, use / for the fraction bar(s).

Arada [10]

If $y=3x^2+30x+71$ , then
$y=3(x^2+10x)+71=3(x^2+2\cdot5x+25-25)+71$
$y=3((x+5)^2-25)+71=3(x+5)^2-75+71=3(x+5)^2-4$ . So, in the first gap you can write 5 and in the second you can write -4.
Since $(x+5)^2\ge 0$ , the minimum value of y is when $(x+5)^2=0$ . The solution of the last equation is x=-5 and then y=-4 -- these are numbers, which you can write in the third and fourth gaps.

5 0

2 years ago

Read 2 more answers

Consider the following random sample from a normal population: 14, 10, 13, 16, 12, 18, 15, and 11. What is the 95% confidence in

seraphim [82]

Answer:

$13.625-2.365\frac{2.669}{\sqrt{8}}=11.393$

$13.625+2.365\frac{2.669}{\sqrt{8}}=15.857$

So on this case the 95% confidence interval would be given by (11.393;15.857)

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".

Data: 14, 10, 13, 16, 12, 18, 15, 11

We can calculate the sample mean and deviation with the following formulas:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$s = \sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

$\bar X=13.625$ represent the sample mean

$\mu$ population mean (variable of interest)

s=2.669 represent the sample standard deviation

n=8 represent the sample size

Calculate the 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:

$df=n-1=8-1=7$

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(0.025,7)".And we see that $t_{\alpha/2}=2.365$

Now we have everything in order to replace into formula (1):

$13.625-2.365\frac{2.669}{\sqrt{8}}=11.393$

$13.625+2.365\frac{2.669}{\sqrt{8}}=15.857$

So on this case the 95% confidence interval would be given by (11.393;15.857)

3 0

2 years ago

The table shows the number of candies packed by Machine C. The equation shows the number of candies packed by Machine D. In both

Rashid [163]

Machine C makes 75 candies per minute.

Machine D makes 130 candies per minute.

Difference is 55

55 * 11 minutes = 605 candies.

4 0

2 years ago

Read 2 more answers

HELP PLEASE. Which regression equation best fits these data?

AlladinOne [14]

Answer:

B. y = -0.58x^2 -0.43x +15.75

Step-by-step explanation:

The data has a shape roughly that of a parabola opening downward. So, you'll be looking for a 2nd-degree equation with a negative coefficient of x^2. There is only one of those, and its y-intercept (15.75) is in about the right place.

The second choice is appropriate.

_____

The other choices are ...

A. a parabola opening upward

C. an exponential function decaying toward zero on the right and tending toward infinity on the left

D. a line with negative slope (This might be a good linear regression model, but the 2nd-degree model is a better fit.)

7 0

2 years ago

Read 2 more answers