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NISA [10]
2 years ago
13

Solve the simultaneous equations 3 2x - y = 7 xy = 15

Mathematics
1 answer:
ehidna [41]2 years ago
8 0

Answer:

(5, 3 ) and (- \frac{3}{2}, - 10 )

Step-by-step explanation:

Given the 2 equations

2x - y = 7 → (1)

xy = 15 → (2)

Rearrange (1) expressing y in terms of x , that is

y = 2x - 7 → (3)

Substitute y = 2x - 7 into (2)

x(2x - 7) = 15

2x² - 7x = 15 ( subtract 15 from both sides )

2x² - 7x - 15 = 0 ← in standard form

(x - 5)(2x + 3) = 0 ← in factored form

Equate each factor to zero and solve for x

x - 5 = 0 ⇒ x = 5

2x + 3 = 0 ⇒ 2x = - 3 ⇒ x = - \frac{3}{2}

Substitute these values into (3) for corresponding values of y

x = 5 : y = 2(5) - 7 = 10 - 7 = 3 ⇒ (5, 3 )

x = - \frac{3}{2} : y = 2(- \frac{3}{2} ) - 7 = - 3 - 7 = - 10 ⇒ (- \frac{3}{2}, - 10 )

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A dairy scientist is testing a new feed additive. She chooses 13 cows at random from a large population of cows. She randomly as
mina [271]

Answer:

Step-by-step explanation:

Given that a dairy scientist is testing a new feed additive. She chooses 13 cows at random from a large population of cows. She randomly assigns nold = 8 to get the old diet, and nnew = 5 to get the new diet including the additive.

From the data given we get the following

           N       Mean      StDev     SE Mean

Sample   1    8           43       5.1824 1.832

Sample   2   5           73     21.0832 9.429

df = 11

Std dev for difference = 13.3689

a) Yes the two are independent.  The two sets of cows randomly chosen are definitely independent. Paired means equal number should be there and homogeneous conditions should be maintained.

b) Enclosed

c) Comparison of two means is the test recommended here.  Because independent samples are used.\

d) Test statistic= -3.1233

(because of unequal variances we use that method)

95% confidence interval =  ( -56.6676 , -3.3324 )

p value <0.05 our alpha

So reject null hypothesis.

The two means are statistically significantly different.

3 0
3 years ago
Find the least common denominator of the fractions 2/8 and 3/5
Ierofanga [76]

Answer:

40

Step-by-step explanation:

2/8 = 10/40

3/5 = 24/40

3 0
3 years ago
Assume that we have two events, and , that are mutually exclusive. Assume further that we know and . If an amount is zero, enter
sweet [91]

Answer:

Explained below.

Step-by-step explanation:

The complete question is:

Assume that we have two events, A and B, that are mutually exclusive. Assume further that we know P(A) = 0.30 and P(B) =0.40.

What is P(A and B)?

What is P(A | B)?

Is P(A | B) equal to P(A)?

Are events A and B dependent or independent?

A student in statistics argues that the concepts of mutually exclusive events and independent events are really the same, and that if events are mutually exclusive they must be independent. Is this statement accurate?

What general conclusion would you make about mutually exclusive and independent events given the results of this problem?

Solution:

The probability of the two events <em>A</em> and <em>B</em> are:

P(A) = 0.30 and P(B) =0.40

(a)

Compute the value of P (A ∩ B) as follows:

P(A\cap B)=0

This is because mutually exclusive events are those events that cannot occur together.

(b)

Compute the value of P (A | B) as follows:

P(A|B)=\frac{P(A\cap B)}{P(B)}=\frac{0}{0.40}=0

Thus, the value of P (A | B) is 0.

(c)

No, P (A | B) is not equal to the P (A).

(d)

As mentioned in part (a), mutually exclusive events are those events which cannot occur together.

That is, P(A\cap B)=0.

Events A and B are independent  if the chance of their concurrent happening is equivalent to the multiplication of their distinct probabilities.

That is, P(A\cap B)=P(A)\times P(B).

The concepts of mutually exclusive events and independent events are not the same.

(e)

As the it is provided that A and B are mutually exclusive events, we know that P(A\cap B)=0.

Now compute the value of P(A)\times P(B) as follows:

               P(A)\times P(B)=0.30\times 0.40=0.12\neq 0

Thus, the events A and B are not independent.

Thus, if two events are mutually exclusive events they cannot be independent.

4 0
3 years ago
HELP ME PLEASE!! MATHEMATICS
ankoles [38]
You show the text of the problem, but you need to show the figure too.
3 0
3 years ago
Angelo earns $2,080 each month. His total deductions are 30% of his pay. How much is deducted from his pay each month? 
Fofino [41]
C. $693.33. Just round. It helps. Round 2,080 to 2,100. Then whats 30% of 2,100? It's easy just think of 21 divided by 3, which equals 7. So, 700 and the closest answers to that is $693.33. That's just the easy way instead of doing the math out. And it is also common sense that B or D wouldn't be it. So your left with C or A. :)
7 0
3 years ago
Read 2 more answers
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