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Ad libitum [116K]
3 years ago
14

I need help please and thank you

Mathematics
1 answer:
Sedaia [141]3 years ago
3 0

Answer:

20 hours

Step-by-step explanation:

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5x - y + z = -6<br> 2x + 7y + 3z = 8<br> x + 2z = 6
BabaBlast [244]

Answer:

Step-by-step explanation:

The system of equations given are:

 

 5x - y + z = -6   ------------- i

 2x + 7y + 3z = 8  ---------- ii

  x + 2z = 6 ----------------- iii

Let us deal with equation i and ii first since they have 3 variables x, y and z;

      5x - y + z = -6                 x 7

       2x + 7y + 3z = 8            x 1

    35x  - 7y + 7z  = -42   ----  iv

      2x  + 7y + 3z  = 8       ---- v

Add equation iv and v;

    37x + 10z  = -34 ------vi

So, let us solve equation vi and iii:

               x + 2z = 6 - ---------- iii   x 10

               37x + 10z  = -34  --- iv  x 2

    10x + 20z   = 60         vi

     74x + 20z  = -68        vii

Subtract vi  - vii;

      -64x  = 128

          x  = -2

So;    put x  = -2 into iii;

           x + 2z  = 6

           -2 + 2z  = 6

            2z  = 6 + 2  = 8

           z  = 4

Put x  = -2 and z = 4 into equation i;

  5(-2) - y + 4  =  - 6

   -10 -y  +4  = -6

       -6  - y  = -6

             -y  = 0

              y  = 0

5 0
3 years ago
Given the Trapezoid ABCD<br><br> Find the length of AD <br><br> Pls hellpppp
matrenka [14]

Given:

In trapezoid ABCD, AD\parallel BC, MN is the mid-segment of ABCD, AD=30x-10,MN=31x+1,BC=30x+28.

To find:

The length of AD.

Solution:

We know that the length of the mid-segment of a trapezoids is half of the sum of lengths of two parallel sides of the trapezoid.

In trapezoid ABCD,

MN=\dfrac{AD+BC}{2}

31x+1=\dfrac{30x-10+30x+28}{2}

31x+1=\dfrac{60x+18}{2}

31x+1=30x+9

Isolate variable terms.

31x-30x=9-1

x=8

Now,

AD=30x-10

AD=30(8)-10

AD=240-10

AD=230

Therefore, the length of AD is 230.

6 0
3 years ago
Which of the following scores has the better relative position ( as measured by the z score) a. A score of 53 on a test for whic
Kisachek [45]

Answer:

d. Cannot be determined with the information provided.

Step-by-step explanation:

Z-score:

In a set with mean \mu and standard deviation \sigma, the z-score 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 p-value, we get the probability that the value of the measure is greater than X.

Finding the better relative position:

The score with the better relative position is the one with a higher z-score.

To find the z-score, the mean and the standard deviation is needed, and in this question, the standard deviation is not given, and thus, the correct answer is given by option d.

3 0
3 years ago
The number can be divided by the least common multiple of 3 and 5
kondaur [170]

9514 1404 393

Answer:

  255

Step-by-step explanation:

If the sum of digits is 12, the number is divisible by 3. If the number ends in 0 or 5, it is divisible by 5. So, we're looking for ...

  2x0 . . . where x is a digit and 2+x+0 = 12 . . . . . . not possible

  2x5 . . . where x is a digit and 2+x+5 = 12 . . . . true for x=5

The number is 255.

3 0
3 years ago
A simple random sample of 100 batteries is selected from a process that produces batteries with a mean lifetime of 32 hours and
Brrunno [24]

Answer:

.b. It is one‐half as large as when n = 100.

Step-by-step explanation:

Given that a  simple random sample of 100 batteries is selected from a process that produces batteries with a mean lifetime of 32 hours and a standard deviation of 3 hours.

i.e. s = 0.3

we obtain se of sample by dividing std devitation by the square root of sample size

i.e. s= \frac{3}{\sqrt{n} }

when n =100 this = 0.3 and

when n =400 this equals 0.15

We find that when sample size is four times as large as original, std deviation becomes 1/2 of the original

Correction option is

.b. It is one‐half as large as when n = 100.

7 0
4 years ago
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