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3 years ago

50 is 125% of what number? 12.5 40 62.5 112.5

Mathematics

1 answer:

kari74 [83]3 years ago

7 0

Answer:

Step-by-step explanation:

divide by 5 if there is a decimal it is wrong

12.5/5=2.5

62.5/5=12.5

40/5=8

112.5/5=22.5

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Write an equation of the line that passes through (-2, 8) and (-4, -4)

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Answer:

y=6x+20

Step-by-step explanation:

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4 years ago

A car traveled 1800 mi at a certain speed. If the speed had been 12 mph faster, the trip could have been made in 5 hr less time.

MArishka [77]

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Step-by-step explanation:

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4 years ago

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The formula for the area of a triangle is a = zon, where b is the length of the base and h is the height.

katen-ka-za [31]

Answer:

The height is 5 units

Step-by-step explanation:

The area of a triangle is

A = 1/2 bh where b is the base and h is the height

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5 0

4 years ago

Consider this scenario: The population of a city increased steadily over a ten-year span. The following ordered pairs show the p

vova2212 [387]

Answer:

Regression function: $y=1986.406+0.0059x$

The function predicts that population will reach 14,000 in year 2068.

Step-by-step explanation:

We have to determine a function $y=b_0+b_1x_1$ by applying linear regression. The data we have is 5 pair of points which relates population to year.

According to the simple regression model (one independent variable), if we minimize the error between the model (the linear function) and the points given, the parameters are:

$b_0=\bar{y}+b_1\bar{x}\\\\b_1=\frac{\sum\limits^5_{i=1} {(x_i-\bar x)(y_i-\bar y)}}{\sum\limits^5_{i=1} {(x_i-\bar x)^2}}$

We start calculating the average of x and y

$\bar x=\frac{2500+2650+3000+3500+4200}{5}=\frac{15850}{5}=3170\\\\ \bar y=\frac{2001+2002+2004+2007+2011}{5}=\frac{10025}{5}=2005$

The sample covariance can be calculated as

$\sum\limits^5_{i=1} {(x_i-\bar x)(y_i-\bar y)}=(2500-3170)(2001-2005)+(2650-3170)(2002-2005)+(3000-3170)(2004-2005)+(3500-3170)(2007-2005)+(4200-3170)(2011-2005)\\\\\sum\limits^5_{i=1} {(x_i-\bar x)(y_i-\bar y)}=2680+1560+170+660+6180\\\\ \sum\limits^5_{i=1} {(x_i-\bar x)(y_i-\bar y)}=11250$

The variance of x can be calculated as

$\sum\limits^5_{i=1} {(x_i-\bar x)^2}=(2500-3170)^2+(2650-3170)^2+(3000-3170)^2+(3500-3170)^2+(4200-3170)^2\\\\\sum\limits^5_{i=1} {(x_i-\bar x)^2}=448900+270400+28900+108900+1060900\\\\\sum\limits^5_{i=1} {(x_i-\bar x)^2}=1918000$

Now we can calculate the parameters of the regression model

$b_1=\frac{\sum\limits^5_{i=1} {(x_i-\bar x)(y_i-\bar y)}}{\sum\limits^5_{i=1} {(x_i-\bar x)^2}}=\frac{11250}{1918000}=0.005865485 \\\\ b_0=\bar{y}+b_1\bar{x}=2005-0.005865485*3170=1986.406413$

The function then become:

$y=1986.406+0.0059x$

With this linear equation we can predict when the population will reach 14,000:

$y=1986.406+0.0059(14,000)=1986.406+82.117=2068.523$

6 0

3 years ago

Help me please, match the number to the letter

kenny6666 [7]

Answer: 1b 2c 3e? 4d 5a

<u>Step-by-step explanation:</u>

There are 2 items that need to be checked.

The midpoint of the coordinates is the center of the circle
The diameter of the coordinates is the diameter of the circle.

Midpoint:

$Midpoint = \bigg(\dfrac{x_1+x_2}{2},\dfrac{y_1+y_2}{2}\bigg)\\\\\\1)\ \bigg(\dfrac{-4+2}{2},\dfrac{-1+10}{2}\bigg)=\bigg(\dfrac{-2}{2},\dfrac{9}{2}\bigg)=(-1, 4.5)\implies \text{equation b}\\\\\\2)\ \bigg(\dfrac{1+7}{2},\dfrac{3-10}{2}\bigg)=\bigg(\dfrac{8}{2},\dfrac{-7}{2}\bigg)=(4, -3.5)\implies \text{equation c}\\\\\\3)\ \bigg(\dfrac{4-8}{2},\dfrac{-2+6}{2}\bigg)=\bigg(\dfrac{-4}{2},\dfrac{4}{2}\bigg)=(-2,2 )\implies \text{none of the equations}$

$4)\ \bigg(\dfrac{6-4}{2},\dfrac{3-13}{2}\bigg)=\bigg(\dfrac{2}{2},\dfrac{-10}{2}\bigg)=(1, -5)\implies \text{equation d}\\\\\\5)\ \bigg(\dfrac{7-1}{2},\dfrac{5+8}{2}\bigg)=\bigg(\dfrac{6}{2},\dfrac{13}{2}\bigg)=(3, 6.5)\implies \text{equation a}$

Diameter:

distance between coordinates = 2√r² (from circle equation)

$\text{formula for coordinates is: }d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\\\\1)\ \text{Coordinates: } d=\sqrt{(-4-2)^2+(-1-10)^2}=\sqrt{36+121}=12.5\\b)\ \text{Circle: }2\sqrt{39.25}=12.5\\\\\\2)\ \text{Coordinates: } d=\sqrt{(1-7)^2+(3+10)^2}=\sqrt{36+169}=14.3\\c)\ \text{Circle: }2\sqrt{51.25}=14.3\\\\\\4)\ \text{Coordinates: } d=\sqrt{(6+4)^2+(3+13)^2}=\sqrt{100+256}=18.9\\d)\ \text{Circle: }2\sqrt{89}=18.9$

$5)\ \text{Coordinates: } d=\sqrt{(7+1)^2+(5-8)^2}=\sqrt{64+9}=8.5\\a)\ \text{Circle: }2\sqrt{18.25}=8.5$

Check:

Graph to confirm your answers are correct (see attached)

8 0

4 years ago