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LiRa [457]
3 years ago
6

The work of a student to solve a set of equations is shown below: Equation 1: x + 2y = 10 Equation 2: 2x + 5y = 15 Step 1: −2(x

+ 2y) = −2(10) 2x + 5y = 15 Step 2: −2x − 4y = −10 2x + 5y = 15 Step 3: 1y = 5 Step 4: x + 2(1) = 10 Step 5: x = 8 In which step did the student first make an error?
Mathematics
2 answers:
DIA [1.3K]3 years ago
6 0
 −2x − 4y = −10 2x + 5y = 15 
Llana [10]3 years ago
6 0

Answer:

Step 2 has error and step 4 has error.

Step-by-step explanation:

Here we can see that elimination method is  applied to solve the  system  of equations  for which -2 is multiplied both sides of equation first

-2(x+2y)=-2(10 which is correct

but in step 2

left side is -2x-4y and the right side is -10 which has to be -20 which makes this step wrong and this is the error made by student.

in Step 4 also ,value of the y has to be 5 but student plugged y =1 which is also error by student.

Correct solution is

    -2x-4y= -20

      2x+ 5y= 15

on adding ,we get

 y = -5

plugging y =5 in equation x+2y= 10 ,we get x+2(-5) =10 ,we get x = 20

therefore (20,-5) is the  solution

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Jen has 6 yards of fabric and wants to make a new dress and shorts she used 3 1/3 yards of the fabric on her new dress how much
kodGreya [7K]

Answer:

2\frac{2}{3}\ yards

Step-by-step explanation:

we know that

To find out how much fabric Jen has left for the shorts, subtract the yards of fabric used in her new dress from the total yards of fabric Jen has.

so

6-3\frac{1}{3}

Convert mixed number to an improper fraction

3\frac{1}{3}=\frac{3*3+1}{3}=\frac{10}{3}

substitute

6-3\frac{1}{3}=6-\frac{10}{3}=\frac{8}{3}\ yards

Convert to mixed number

\frac{8}{3}\ yards=\frac{6}{3}+\frac{2}{3}=2\frac{2}{3}\ yards

5 0
3 years ago
PLEASE HELP ASAPPPPP Find the value of x for mAB= 27° and mCD= 49°. The figure is not drawn to scale
Minchanka [31]

Answer: the answer is B

Step-by-step explanation:

51.5

6 0
2 years ago
Read 2 more answers
The weight of an adult swan is normally distributed with a mean of 26 pounds and a standard deviation of 7.2 pounds. A farmer ra
Snezhnost [94]
Let X denote the random variable for the weight of a swan. Then each swan in the sample of 36 selected by the farmer can be assigned a weight denoted by X_1,\ldots,X_{36}, each independently and identically distributed with distribution X_i\sim\mathcal N(26,7.2).

You want to find

\mathbb P(X_1+\cdots+X_{36}>1000)=\mathbb P\left(\displaystyle\sum_{i=1}^{36}X_i>1000\right)

Note that the left side is 36 times the average of the weights of the swans in the sample, i.e. the probability above is equivalent to

\mathbb P\left(36\displaystyle\sum_{i=1}^{36}\frac{X_i}{36}>1000\right)=\mathbb P\left(\overline X>\dfrac{1000}{36}\right)

Recall that if X\sim\mathcal N(\mu,\sigma), then the sampling distribution \overline X=\displaystyle\sum_{i=1}^n\frac{X_i}n\sim\mathcal N\left(\mu,\dfrac\sigma{\sqrt n}\right) with n being the size of the sample.

Transforming to the standard normal distribution, you have

Z=\dfrac{\overline X-\mu_{\overline X}}{\sigma_{\overline X}}=\sqrt n\dfrac{\overline X-\mu}{\sigma}

so that in this case,

Z=6\dfrac{\overline X-26}{7.2}

and the probability is equivalent to

\mathbb P\left(\overline X>\dfrac{1000}{36}\right)=\mathbb P\left(6\dfrac{\overline X-26}{7.2}>6\dfrac{\frac{1000}{36}-26}{7.2}\right)
=\mathbb P(Z>1.481)\approx0.0693
5 0
2 years ago
Write two equivalent ratios. 7 : 6
jekas [21]

Answer:

4:3 or 1:0

Step-by-step explanation:

4 0
3 years ago
The drug Viagra comes in a quantity of 30 tablets with an AWP of $900. The pharmacy has an agreement with the supplier to purcha
MrRissso [65]

The profit of  5103.5 by making a prescription for 6 tablets.

<h3>What is percentage?</h3>

Percentage, a relative value indicating hundredth parts of any quantity.

The drug Viagra comes in a quantity of 30 tablets with an AWP of $900.

The insurer is willing to pay the AWP less 5% plus a $2.50

900/TAB = X 30 TABS  =$27000

27000 * (0.05)= $1350

27000-1350.00

=$25650 + $2.50

=25652.5 for 30 tablets

For 6 tablets,

= (25652.5 / 30)*6

= 5103.5

Learn more about percentage here:

brainly.com/question/14695543

#SPJ1

5 0
2 years ago
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