All categories

3 years ago

How to solve it using elimination

Mathematics

1 answer:

gregori [183]3 years ago

8 0

X=3
y=5

You have to cancel out either the x values or the y values (I chose y). You multiply both equations by particular numbers so either the x values or y values can be equal to each other, as well as positive or negative to each other. I multiplied -7y by 4 and 4y by 7, and got -28y and 28y. I then canceled those out. The numbers you multiply by also affects the rest of the equations, so I ended up with 48x=4 and -35x=35. After that, you combine like terms, which results in 13x=39. You divide 13 by both sides and you end up with x=3. To find y, all you have to do is plug in the x value to one of the equations, then solve for y. I resulted in y=5.

Hope this helped ^_^

You might be interested in

In a simple random sample of 14001400 young people, 9090% had earned a high school diploma. Complete parts a through d below.

ratelena [41]

Answer:

(a) The standard error is 0.0080.

(b) The margin of error is 1.6%.

(c) The 95% confidence interval for the percentage of all young people who earned a high school diploma is (88.4%, 91.6%).

(d) The percentage of young people who earn high school diplomas has increased.

Step-by-step explanation:

Let p = proportion of young people who had earned a high school diploma.

A sample of n = 1400 young people are selected.

The sample proportion of young people who had earned a high school diploma is:

$\hat p=0.90$

(a)

The standard error for the estimate of the percentage of all young people who earned a high school diploma is given by:

$SE_{\hat p}=\sqrt{\frac{\hat p(1-\hat p)}{n}}$

Compute the standard error value as follows:

$SE_{\hat p}=\sqrt{\frac{\hat p(1-\hat p)}{n}}$

$=\sqrt{\frac{0.90(1-0.90)}{1400}}\\$

$=0.008$

Thus, the standard error for the estimate of the percentage of all young people who earned a high school diploma is 0.0080.

(b)

The margin of error for (1 - α)% confidence interval for population proportion is:

$MOE=z_{\alpha/2}\times SE_{\hat p}$

Compute the critical value of z for 95% confidence level as follows:

$z_{\alpha/2}=z_{0.05/2}=z_{0.025}=1.96$

Compute the margin of error as follows:

$MOE=z_{\alpha/2}\times SE_{\hat p}$

$=1.96\times 0.0080\\=0.01568\\\approx1.6\%$

Thus, the margin of error is 1.6%.

(c)

Compute the 95% confidence interval for population proportion as follows:

$CI=\hat p\pm MOE\\=0.90\pm 0.016\\=(0.884, 0.916)\\\approx (88.4\%,\ 91.6\%)$

Thus, the 95% confidence interval for the percentage of all young people who earned a high school diploma is (88.4%, 91.6%).

(d)

To test whether the percentage of young people who earn high school diplomas has increased, the hypothesis is defined as:

H₀: The percentage of young people who earn high school diplomas has not increased, i.e. p = 0.80.

Hₐ: The percentage of young people who earn high school diplomas has not increased, i.e. p > 0.80.

Decision rule:

If the 95% confidence interval for proportions consists the null value, i.e. 0.80, then the null hypothesis will not be rejected and vice-versa.

The 95% confidence interval for the percentage of all young people who earned a high school diploma is (88.4%, 91.6%).

The confidence interval does not consist the null value of p, i.e. 0.80.

Thus, the null hypothesis is rejected.

Hence, it can be concluded that the percentage of young people who earn high school diplomas has increased.

8 0

3 years ago

The probability that Terry buys a sandwich is 0.4.

lara31 [8.8K]

0.4 * 0.6 this gives

0.24

5 0

3 years ago

Brady is selling candy bars for a school fundraiser to help pay for new sports uniforms. He gets paid $2 for every candy bar he

swat32

Answer:

Second option: $2x=90$

Step-by-step explanation:

Let be "x" the number of candy bars Brady sold on Saturday.

For this exercise you need to analize the information provided in the exercise.

According to the information provided, Brady gets paid $2 for every candy bar he sells. This can be expressed as:

$2x$

You know that Brady made a total of $90 on Saturday; this mean the product of $2x$ is 90.

Based on this, you can write the following equation that represents the number of candy bars Brady sold on Saturday:

$2x=90$

Observe that this matches with the second option.

6 0

3 years ago

Ms. Howard wrote a test. Part A had true/false questions, each worth points. Part B had multiple choice questions, each worth po

harina [27]

Full question attached

Answer and explanation:

Since x = number of true or false questions correct

And y = number of multiple choice questions correct

And each question for x =2 points

each question for y=3 points

since she then needs a total score of more than 93 to pass, we add up total correct questions and

Inequality equation = 2x +3y >93

5 0

3 years ago

A graphic designer creates an image for a t-shirt that measures 8 inches tall and 10 inches wide. She can use this image for sma

jeka57 [31]

1.125 times 8=9
1.125times10=11.25

1.125=112.5%

So she will have to enlarge the logo for the large shirt by 12.5%

8 0

3 years ago