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2 years ago

Which properties justify the steps taken to solve the system?

Mathematics

1 answer:

Nutka1998 [239]2 years ago

6 0

Answer:

X=-1

Y=1

Step-by-step explanation:

6x-12y

-18

) 6x + 4y

-2

Subtract the two equations

6x - 12y - (6x + 4y) = -18 - (-2)

Determine the sign

6x- 12y - 6x- 4y

=-18 + 2

Simplify

-12y

- Ay

=-18 + 2

Solve the equation

Substitute

6×+4

-2

Solve the equation

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A(4,-7) B(-2,1) find AB

Natali5045456 [20]

$\bf ~~~~~~~~~~~~\textit{distance between 2 points}\\\\A(\stackrel{x_1}{4}~,~\stackrel{y_1}{-7})\qquadB(\stackrel{x_2}{-2}~,~\stackrel{y_2}{1})\qquad \qquadd = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2}\\\\\\AB=\sqrt{[-2-4]^2+[1-(-7)]^2}\implies AB=\sqrt{(-2-4)^2+(1+7)^2}\\\\\\AB=\sqrt{(-6)^2+8^2}\implies AB=\sqrt{36+64}\implies AB=\sqrt{100}\implies AB=10$

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3 years ago

You buy a six pack of Gatorade for $9.00. What is the unit price or the price per bottle?

Viefleur [7K]

Answer:

Price per bottle is 1.5 or $1.50

Step-by-step explanation:

To get price per unit, you just divide the amount of money spent by the items purchased. 9/6 = 1.5

4 0

3 years ago

45x+10y+50=?<br> PLZ HELP ASAP DUE TODAY!

Viktor [21]

Answer:

5(9x + 2y + 10)

x = 0

y = -5

Step-by-step explanation:

If you are just factoring this, you will factor a 5 out from everything.

5(9x + 2y + 10)

or if you are trying to solve just isolate one of the variables and then substitute it into the original equation

45x + 10y = 50

10y = 50 - 45x

y = 5 - 4.5x

45x + 10(5-4.5x) + 50

45x + 50 - 45x + 50

x=0

45(0) + 10y + 50

0 + 10y + 50

10y + 50

10y = -50

y = -5

and it would be x = 0 and y = -5

7 0

2 years ago

The College Boards, which are administered each year to many thousands of high school students, are scored so as to yield a mean

Marysya12 [62]

Answer:

a) 15.87% of the scores are expected to be greater than 600.

b) 2.28% of the scores are expected to be greater than 700.

c) 30.85% of the scores are expected to be less than 450.

d) 53.28% of the scores are expected to be between 450 and 600.

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 500, \sigma = 100$

a. Greater than 600

This is 1 subtracted by the pvalue of Z when X = 600. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{600 - 500}{100}$

$Z = 1$

$Z = 1$ has a pvalue of 0.8413.

1 - 0.8413 = 0.1587

15.87% of the scores are expected to be greater than 600.

b. Greater than 700

This is 1 subtracted by the pvalue of Z when X = 700. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{700 - 500}{100}$

$Z = 2$

$Z = 2$ has a pvalue of 0.9772

1 - 0.9772 = 0.0228

2.28% of the scores are expected to be greater than 700.

c. Less than 450

Pvalue of Z when X = 450. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{450 - 500}{100}$

$Z = -0.5$

$Z = -0.5$ has a pvalue of 0.3085.

30.85% of the scores are expected to be less than 450.

d. Between 450 and 600

pvalue of Z when X = 600 subtracted by the pvalue of Z when X = 450. So

X = 600

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{600 - 500}{100}$

$Z = 1$

$Z = 1$ has a pvalue of 0.8413.

X = 450

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{450 - 500}{100}$

$Z = -0.5$

$Z = -0.5$ has a pvalue of 0.3085.

0.8413 - 0.3085 = 0.5328

53.28% of the scores are expected to be between 450 and 600.

6 0

3 years ago

If the length of AO is double the length of CO, the length of BO is?

andreev551 [17]

BO is double that of DO. In other words, BO is two times longer than DO. The answer is choice B

For example, if DO were 3 units long, then BO would be 6 units long (2*3 = 6). This works because the triangles DCO and BAO are similar triangles. The corresponding sides are in the same ratio or proportion to one another. The larger triangle (BAO) has sides that are twice as long as the smaller triangle's (DCO) corresponding sides.

Side note: we can prove the triangles to be similar using the AA (angle angle) similarity theorem. The first pair of angles are the vertical angles DOC and BOA which are congruent to each other.The second pair is CDB and ABD which are congruent by the alternate interior angle theorem. Check out the attached image for a visual.

7 0

3 years ago