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3 years ago

Please help me I need the answer and work !!!!

Mathematics

2 answers:

nika2105 [10]3 years ago

8 0

X=1, Y=-2. Heres your answer. It should be C

vovikov84 [41]3 years ago

4 0

Answer:

(1, -2)

Step-by-step explanation:

So we can work straight away

The elimination method deals with eliminating one variable so that you can find the other, then substituting that back in to find the one we eliminated originally. So, let's add our two equations together:

9x - 3y = 15

+ 3x + 3y = -3

12x = 12

So now that we've reached a new equation, 12x = 12, we can divide both sides by 12 and get that:

x = 1

Substituting this back into the second equation (though you could sub it into either one):

3(1) + 3y = -3

3 + 3y = -3

3y = -6

y = -2

Therefore, x = 1 and y = -2, also represented as (1, -2)

Hope this helps!

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Find the greatest common factor 28 and 12 use the GCF to factor 28+12.

fgiga [73]

Answer:

(a) 4

(b) 4 * (7+3)

Step-by-step explanation:

(a) Let's first start by prime factorizing (finding the prime factors) 28 and 12:

12: 2*2*3

28: 2*2*7

We can see here they both share a common factor of 2*2, which is 4, therefore the GCF is 4.

(b) Factor a 4 out from the equation:

$4*(\frac{28}{4}+\frac{12}{4})$

This gives us:

4 * (7+3)

5 0

2 years ago

What’s the probability of getting 6 or more girls from 8 births?

Lemur [1.5K]

Answer:

3/4 or 6/8

Step-by-step explanation:

6/8 when simplified is 3/4. That is the probability over the total.

8 0

3 years ago

A dog breeder would like to know how many Dalmatian puppies are typically born in a litter. He conducts some research and select

podryga [215]

Answer:

c. 6.2 ± 2.626(0.21)

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 101 - 1 = 100

99% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 100 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.99}{2} = 0.995$ . So we have T = 2.626

The confidence interval is:

$\overline{x} \pm M$

In which $\overline{x}$ is the sample mean while M is the margin of error.

The distribution of the number of puppies born per litter was skewed left with a mean of 6.2 puppies born per litter.

This means that $\overline{x} = 6.2$

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 2.626\frac{2.1}{\sqrt{101}} = 2.626(0.21)$

In which s is the standard deviation of the sample and n is the size of the sample.

Thus, the confidence interval is:

$\overline{x} \pm M = 6.2 \pm 2.626(0.21)$

And the correct answer is given by option c.

5 0

3 years ago

James states that quadrilateral

mr_godi [17]

Using the distance formula,

$AD=\sqrt{(-1-3)^{2}+(-3-(-4))^{2}}=\sqrt{17}\\\\BC=\sqrt{(5-9)^{2}+(1-0)^{2}}=\sqrt{17} \\\\\therefore \overline{AD} \cong \overline{BC}$

$AB=\sqrt{(-1-5)^{2}+(-3-1)^{2}}=\sqrt{52}=2\sqrt{13}\\\\CD=\sqrt{(9-3)^{2}+(0-(-4))^{2}}=\sqrt{52}=2\sqrt{13}\\\\\therefore \overline{AB} \cong \overline{CD}$

Since ABCD has two pairs of opposite congruent sides, it is a parallelogram.

3 0

2 years ago

A bee flies 20 feet per second directly to a flowerbed from its hive. The bee stays at the flowerbed for fifteen minutes. Then i

Ksenya-84 [330]

A. The equation to find the distance of the flowerbed from the hive is: $\frac{x}{20}+\frac{x}{12}+900= 1200$ , where x is the distance.

B. The flowerbed is 2250 feet far from the hive.

Explanation

Suppose, the distance of the flowerbed from the hive is $x$ feet.

The bee flies 20 feet per second directly to a flowerbed from its hive and flies directly back to the hive at 12 feet per second.

As, $Time=\frac{Distance}{Speed}$

So, the time taken by the bee to reach the flowerbed $= \frac{x}{20}$ seconds and the time taken to fly back to the hive $=\frac{x}{12}$ seconds.

The bee stays at the flowerbed for 15 minutes or (15×60)seconds or 900 seconds and it is away from the hive for a total of 20 minutes or (20×60)seconds or 1200 seconds.

So, the equation will be.......

$\frac{x}{20}+\frac{x}{12}+900= 1200\\ \\ \frac{3x+5x}{60}= 300\\ \\ 8x= 60*300\\ \\ 8x=18000\\ \\ x=\frac{18000}{8}=2250$

Thus, the distance of the flowerbed from the hive is 2250 feet.

5 0

3 years ago