Please help 2x^2-6y+(16+4÷2)+y

Help! Need by 10:30 to turn in and I'm confused!

Alecsey [184]

Answer:

8 boxes of tissues

5 bags of cough drops

Step-by-step explanation:

You need to write a system of equations.

x = number of tissue boxes

y = number of cough drop bags

x (number of tissue boxes) + y (number of cough drop bags) = 13 (total number of tissues and cough drops combined.

So, your first equation is

x + y = 13

Then, you need to write the second equation.

(1.69 [cost of 1 tissue box] * [number of tissue boxes]) + (1.19 [cost of one bag of cough drops] * [number of cough drop bags] = 19.47 [total cost of tissues and cough drops]

That's a lot to read, so here's the equation simplified!

1.69x + 1.19y = 19.47

Now, you have two equations:

x + y = 13

1.69x + 1.19y = 19.47

I would solve with the substitution method.

the first equation can be changed to x = 13 - y by subtracting y from both sides.

Then, your two equations are:

x = 13 - y

1.69x + 1.19y = 19.47

Now, you can plug in that value of x into the second equation!

1.69(13 - y) + 1.19y = 19.47

21.97 - 1.69y + 1.19y = 19.47

subtract 21.97 from both sides

-1.69y + 1.19y = -2.5

Add the y values

-0.5y = -2.5

divide both sides by -0.5

so, y equals 5 bags of cough drops

now that you know what y equals, plug it back into your original equation to find x!

x + y = 13

plug in y

x + 5 = 13

x = 8

so, x = 8 boxes of tissues

Hope this helps! Let me know if you have any questions!

8 0

3 years ago

A film start at 17:15 and finish at 1 hour and 45 minutes later. what time did it finish?

vova2212 [387]

It ended at 19:00 or at 7 pm

4 0

2 years ago

Someone plz help me out i need to pass

Anni [7]

Answer:

it takes 24h

Step-by-step explanation:

3 0

3 years ago

Find the circumference of a circle whose area is 24

zalisa [80]

The answer is: " 17.35 " .

__________________________________

→ The circumference of the circle is: " 17.35 units " .

__________________________________

The area, "A", of a circle:

A = $\pi$ * r² ;

Note: $\pi = 3.14$ .

The area of the circumference, "C", of a circle:

C = 2 $\pi$ r .

__________________________________________

Given:

A = 24 ;

Use the formula for the area, "A" of a circle, to find the radius, "r" .

Then, plug the value obtained for "r" into the formula for the circumference, "C" , of a circle:

C = 2 $\pi$ r l

To solve for the circumference, "C", of the circle.

________________

A = $\pi * r^{2}$ ;

24 = 3.14 * r² ;

↔ 3.14 * r² = 24 ;

Divide each side of the equation by "(3.14)" ;

[3.14 * r²] / 3.14 = (24) / (3.14) ;

to get:

→ r² = 7.64331210191 ;

Take the positive square root of each side of the equation;

to isolate "r" on one side of the equation; & to solve for the radius, "r" ;

→ ⁺√(r²) = ⁺√(7.64331210191) ;

to get:

→ r = 2.76281034802 ;

____________________________

Now, plug this "obtained value" for the radius, "r" into the equation for the formula for the circumference, "C" of a circle:

→ C = 2 $\pi$ * r ;

to solve for the circumference, "C", of the circle:

→ C = 2 * (3.14) * (2.76281034802) ;

= (6.28) * (2.76281034802) ;

= 17.3504489856 ;

→ round to: " 17.35 units" .

__________________________________

The answer is: " 17.35 " .

__________________________________

→ The circumference of the circle is: " 17.35 units " .

__________________________________

6 0

3 years ago

Men are believed to have a slightly longer average length of short hospital stays than women; 5.2 days versus 4.5 days respectiv

Georgia [21]

Answer:

Since our calculated value is lower than our critical value, $z_{calc}=2.02$ , we have enough evidence to FAIL to reject the null hypothesis at 1% of singificance. So there is not nough evidence to conclude that mean for men it's significantly higher than the mean for female.

Step-by-step explanation:

1) Data given and notation

$\bar X_{1}=5.2$ represent the mean for group men

$\bar X_{2}=4.5$ represent the mean for group women

Assuming these values for the remaining data:

$\sigma_{1}=1.2$ represent the population standard deviation for the sample men

$\sigma_{2}=1.5$ represent the population standard deviation for the sample women

$n_{1}=32$ sample size for the group men

$n_{2}=30$ sample size for the group women

z would represent the statistic (variable of interest)

$p_v$ represent the p value

2) Concepts and formulas to use

We need to conduct a hypothesis in order to check if the mean for men it's higher than the mean for women, the system of hypothesis would be:

H0: $\mu_{1} \leq \mu_{2}$

H1: $\mu_{1} > \mu_{2}$

If we analyze the size for the samples both are higher than 30, and we know the population deviation's, so for this case is better apply a z test to compare means, and the statistic is given by:

$z=\frac{\bar X_{1}-\bar X_{2}}{\sqrt{\frac{\sigma^2_{1}}{n_{1}}+\frac{\sigma^2_{2}}{n_{2}}}}$ (1)

z-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

3) Calculate the statistic

We have all in order to replace in formula (1) like this:

$z=\frac{5.2-4.5}{\sqrt{\frac{1.2^2}{32}+\frac{1.5^2}{30}}}=2.02$

4) Find the critical value

In order to find the critical value we need to take in count that we are conducting a right tailed test, so we are looking on the normal standard distribution a value that accumulats 0.01 of the area on the right and 0.99 of the area on the left. We can us excel or a table to find it, for example the code in Excel is:

"=NORM.INV(1-0.01,0,1)", and we got $z_{critical}=2.33$

5) Statistical decision

Since our calculated value is lower than our critical value, $z_{calc}=2.02$ , we have enough evidence to FAIL to reject the null hypothesis at 1% of significance. So there is not nough evidence to conclude that mean for men it's significantly higher than the mean for female.

6 0

3 years ago