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Rufina [12.5K]
3 years ago
10

Can someone please help me with this problem? You need to find the value of x and y by using the strategy of ELIMINATION. Please

show your work.
Here are the two equations:
7x + 8y = 20
7x - 2y = 29

Thanks in advance!
Mathematics
1 answer:
Setler [38]3 years ago
5 0

Answer:

x = 136/35; y = -⁹/₁₀

Step-by-step explanation:

(1)         7x + 8y = 20

(2)        7x – 2y = 29       Subtract (2) from (1)

                  10y =  -9        Divide each side by 10

(3)                 y =  -⁹/₁₀     Substitute (3) into (1)

      7x - 2(-⁹/₁₀) = 29

      7x + 18/10  = 29                       Subtract 18/10 from each side

      7x              =      29 - 18/10

      7x              = (290 - 18)/10

      7x              =          272/10        Divide each side by 7

        x              =           272/70

        x              =           136/35

x = 136/35; y = -⁹/₁₀

Check:

(1) 7(136/35) + 8(-⁹/₁₀) = 20

      136/5    -   72/10 = 20

      136/5    -   36/5  = 20

                      100/5  = 20

                       20      = 20

(2) 7(136/35) – 2(-⁹/₁₀)  = 29

       136/5    +    18/10 = 29

       136/5    +      ⁹/₅    = 29

                        145/5  = 29

                        29       = 29

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The percentile serves to group a data distribution into 100 equal spaces parts. It represents the value or the point below which a particular proportion of the distribution falls.

The 13th percentile thus represent a value or a point in the distribution that is higher than 13% of the distribution.

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The variance is an average of the squared deviations from the mean.

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Like I explained in (a), scoring 55th percentile mean that one has scored more than 55% of the people that sat for the exam.

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45% of 8000 = 3600 people.

3600 people had a score at least as high as the 55th percentile's score.

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