All categories

3 years ago

I neep helpppppppppp

Mathematics

2 answers:

skelet666 [1.2K]3 years ago

7 0

Answer:

Step-by-step explanation:

$x = 5 - 2y \\ y = 3(5 - 2y) - 8 \\ y = 15 - 6y - 8 \\ y = 7 - 6y \\ 7y = 7 \\ y = 1$

$x = 5 - 2y \\ x = 5 - 2 = 3 \\$

Ksivusya [100]3 years ago

7 0

Answer:

D is right (there is exactly one soution at (3,1))

Step-by-step explanation:

x+2y=5

3+2(1)=5

y=3x-8

1=3(3)-8

You might be interested in

Help me please!! on the puzzle please

grin007 [14]

U actually did it right to let u know and u r so welcome

8 0

3 years ago

The sum of 4 consecutive integers is 26. What is the least of 4 integers?

Veseljchak [2.6K]

Answer:

Step-by-step explanation:

it is 5 because 5 + 6 + 7 + 8 =26

and 5 is the least

4 0

4 years ago

Read 2 more answers

Noah borrowed $0.80 from his friend John five days last week to buy chips. how much does Noah owe John?

vekshin1

Answer:

$0.80

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers

An experiment was conducted to observe the effect of an increase in temperature on the potency of an antibiotic. Three 1-ounce p

ludmilkaskok [199]

Answer:

a) $y=-0.317 x +46.02$

b) Figure attached

c) $S^2=\hat \sigma^2=MSE=\frac{190.33}{10}=19.03$

Step-by-step explanation:

We assume that th data is this one:

x: 30, 30, 30, 50, 50, 50, 70,70, 70,90,90,90

y: 38, 43, 29, 32, 26, 33, 19, 27, 23, 14, 19, 21.

a) Find the least-squares line appropriate for this data.

For this case we need to calculate the slope with the following formula:

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

So we can find the sums like this:

$\sum_{i=1}^n x_i = 30+30+30+50+50+50+70+70+70+90+90+90=720$

$\sum_{i=1}^n y_i =38+43+29+32+26+33+19+27+23+14+19+21=324$

$\sum_{i=1}^n x^2_i =30^2+30^2+30^2+50^2+50^2+50^2+70^2+70^2+70^2+90^2+90^2+90^2=49200$

$\sum_{i=1}^n y^2_i =38^2+43^2+29^2+32^2+26^2+33^2+19^2+27^2+23^2+14^2+19^2+21^2=9540$

$\sum_{i=1}^n x_i y_i =30*38+30*43+30*29+50*32+50*26+50*33+70*19+70*27+70*23+90*14+90*19+90*21=17540$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=49200-\frac{720^2}{12}=6000$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}=17540-\frac{720*324}{12}{12}=-1900$

And the slope would be:

$m=-\frac{1900}{6000}=-0.317$

Nowe we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{720}{12}=60$

$\bar y= \frac{\sum y_i}{n}=\frac{324}{12}=27$

And we can find the intercept using this:

$b=\bar y -m \bar x=27-(-0.317*60)=46.02$

So the line would be given by:

$y=-0.317 x +46.02$

b) Plot the points and graph the line as a check on your calculations.

For this case we can use excel and we got the figure attached as the result.

c) Calculate S^2

In oder to calculate S^2 we need to calculate the MSE, or the mean square error. And is given by this formula:

$MSE=\frac{SSE}{df_{E}}$

The degred of freedom for the error are given by:

$df_{E}=n-2=12-2=10$

We can calculate:

$S_{y}=\sum_{i=1}^n y^2_i -\frac{(\sum_{i=1}^n y_i)^2}{n}=9540-\frac{324^2}{12}=792$

And now we can calculate the sum of squares for the regression given by:

$SSR=\frac{S^2_{xy}}{S_{xx}}=\frac{(-1900)^2}{6000}=601.67$

We have that SST= SSR+SSE, and then SSE=SST-SSR= 792-601.67=190.33[/tex]

So then :

$S^2=\hat \sigma^2=MSE=\frac{190.33}{10}=19.03$

5 0

3 years ago

PLEASE HELP!!!! 25 POINTS!!!!

Andrei [34K]

Answer:

0.9562

Step-by-step explanation:

Binomial probability is mathematically expressed as:

$P(X=x)={n\choose x}p^x(1-p)^{n-x}$

Given that p=0.18, n=5 , is calculated as:

$P(X\leq 2)=P(0)+P(1)+P(2)\\\\={5\choose 0}0.18^0(1-0.18)^5+{5\choose 1}0.18^1(1-0.18)^4+{5\choose 2}0.18^2(1-0.18)^3\\\\=0.3707+0.4069+0.1786\\\\=0.9562$

Hence, the probability of no more than 2 successes in 5 trials is 0.9562

4 0

3 years ago