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Ratling [72]
3 years ago
5

Solve x and y simultaneously if:

Mathematics
1 answer:
Solnce55 [7]3 years ago
5 0

Answer:

make Y the subject in eqn........ 1

y + 7 = 2x

y = 2x - 7...........eqn 3

put y = 2x - 7 into eqn 2

x² - xy + 3y² = 15

x² - x(2x - 7) + 3(2x - 7)(2x - 7) = 15

x² - 2x² + 7x + 3(4x² + 14x -14x + 21) = 15

x² - 2x² + 7x + 12x² + 42x - 42x + 63 = 15

x² - 2x² + 7x + 12x² + 63 = 15

x² - 2x² + 12x² + 7x + 63 = 15

11x² + 7x + 63 - 15 = 0

11x² + 7x + 48 = 0

11x² + 7x = - 48

11x²/11 + 7x/11 = - 48/11

x² + 7x

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Suppose GRE Verbal scores are normally distributed with a mean of 461 and a standard deviation of 118. A university plans to rec
nirvana33 [79]

Answer:

The minimum score required for recruitment is 668.

Step-by-step explanation:

Problems of normally distributed samples can be 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 = 461 \sigma = 118

Top 4%

A university plans to recruit students whose scores are in the top 4%. What is the minimum score required for recruitment?

Value of X when Z has a pvalue of 1-0.04 = 0.96. So it is X when Z = 1.75.

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

1.75 = \frac{X - 461}{118}

X - 461 = 1.75*118

X = 667.5

Rounded to the nearest whole number, 668

The minimum score required for recruitment is 668.

8 0
3 years ago
Okay sorry about the other one
Neporo4naja [7]
Number ten is 60 73+36=108
6 0
3 years ago
EXPERT HELP I'LL GIVE BRAINLIEST:
Viefleur [7K]
You are correct my friend
3 0
3 years ago
What of the following ratios are equivalent to 12:15
Dafna11 [192]
Answer to the problem you are asking is d
6 0
3 years ago
Read 2 more answers
A family drinks 2 gallons of milk in 3 days,
Alenkinab [10]

Answer: This is what I have tried --

5 gallons : 3 weeks = x gallons : 52 weeks

5/3 = x/52 (cross multiply)

3x = 260 (divide by 3)

x = 86.6 or 87 gallons

Step-by-step explanation: hope this is right

7 0
3 years ago
Read 2 more answers
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