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3 years ago

Solve these simultaneous equations 2x+3y=13 4x-y=-2

Mathematics

2 answers:

horrorfan [7]3 years ago

8 0

Answer:

x = $\frac{1}{2}$ , y = 4

Step-by-step explanation:

2x + 3y = 13

4x - y = -2

Lets get the equation of the y value;

4x - y = -2

Subtract 4x to both sides;

-y = -4x - 2

Divide both sides by -1

y = 4x + 2

Substitute y in the second equation;

2x + 3y = 13

2x + 3(4x + 2) = 13

Distribute;

2x + 12x + 6 = 13

14x + 6 = 13

Subtract 6 from both sides;

14x = 7

Divide both sides by 14;

x = $\frac{1}{2}$

Lets calculate the value of x;

$(4)\frac{1}{2} - y= -2\\\frac{4}{2} - y =-2\\ 2 - y=-2\\$

Subtract 2 from both sides;

-y = -4

Divide both sides by -1

y = 4

Neko [114]3 years ago

6 0

X = 1/2 y = 4 by elimination

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2 years ago

19. (9+2) X 6 -5=<br> Help

Nata [24]

Answer:

Step-by-step explanation:

Use PEMDAS (Parenthesis first, Exponents second, Division/Multiplication third, Addition/Subtraction last)

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3 years ago

Read 2 more answers

According to the U.S. Bureau of Labor Statistics, 20% of all people 16 years of age or older do volunteer work. In this age grou

Murljashka [212]

Answer:

1. P(X≥35) = 0.0183

2. P(X≤21) = 0.0183

3. P(0.18<p<0.25) = 0.7915

Step-by-step explanation:

We have the proportion for women: pw=0.22, and the proportion for men: pm=0.19.

1. We have a sample of 140 woman and we have to calculate the probability of getting 35 or more who do volunteer work.

This is equivalent to a proportion of

$p=X/n=35/140=0.25$

The standard error of the proportion is:

$\sigma_p=\sqrt{\dfrac{p(1-p)}{n}}=\sqrt{\dfrac{0.22*0.78}{300}}\\\\\\ \sigma_p=\sqrt{0.0006}=0.0239$

We calculate the z-score as:

$z=\dfrac{p-p_w}{\sigma_p}=\dfrac{0.25-0.22}{0.0239}=\dfrac{0.03}{0.0239}=0.8198$

Then, the probability of having 35 women or more who do volunteer work in this sample of 140 women is:

$P(X>35)=P(p>0.25)=P(z>2.0906)=0.0183$

2. We have to calculate the probability of having 21 or fewer women in the group who do volunteer work.

The proportion is now:

$p=X/n=21/140=0.15$

We can calculate then the z-score as:

$z=\dfrac{p-p_w}{\sigma_p}=\dfrac{0.15-0.2}{0.0239}=\dfrac{-0.05}{0.0239}=-2.0906$

Then, the probability of having 21 women or less who do volunteer work in this sample of 140 women is:

$P(X$

3. For the sample with men and women, we use the proportion for both, which is π=0.2.

The sample size is n=300.

Then, the standard error of the proportion is:

$\sigma_p=\sqrt{\dfrac{p(1-p)}{n}}=\sqrt{\dfrac{0.2*0.8}{300}}\\\\\\ \sigma_p=\sqrt{0.0005}=0.0231$

We can calculate the z-scores for p1=0.18 and p2=0.25:

$z_1=\dfrac{p_1-\pi}{\sigma_p}=\dfrac{0.18-0.2}{0.0231}=\dfrac{-0.02}{0.0231}=-0.8660\\\\\\z_2=\dfrac{p_2-\pi}{\sigma_p}=\dfrac{0.25-0.2}{0.0231}=\dfrac{0.05}{0.0231}=2.1651$

We can now calculate the probabilty of having a proportion within 0.18 and 0.25 as:

$P=P(0.18$

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3 years ago

Ryan eats 4 chocolate cream cookies per day. If an equation were written to show the total number of cookies Ryan has eaten afte

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B because you already know number of cookies eaten, you dont know if the total was 12 cookies because you dont know how many days so, if you dont know how many days then y would be the number of days... Good Luck

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3 years ago

Find an equation of a line that has a slope 7 and passes through the point 3,11

choli [55]

You’re given that m=7 (slope is 7), so setup the slope-intercept form with that info: y = 7x + b.

Now you need to find b. Plug in (3,11) for x and y, x=3 and y=11.

11 = 7*3 + b

Notice the only variable left is b, so you’ll find b this way.

11 = 21 + b and then subtract 21 from both sides:

11 - 21 = b

-10 = b

Plug that back into the equation and you have y = 7x -10

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3 years ago