10x−y = 10 −2x+ 5y = −2

Evaluate the following expression: -4xy when x = 1/4 and y = -3.

Travka [436]

Answer:

3

Step-by-step explanation:

-4(1/4)(-3)= 3

Mark as brainlist.

7 0

3 years ago

At one store, 5 pairs of jeans and 2 sweatshirts costs $207, while 3 pairs of jeans and 4 sweatshirts costs $169. Find the cost

Genrish500 [490]

Answer:

One pair of jeans cost $35.

One sweatshirt cost $16.

Step-by-step explanation:

j = jeans

s = sweatshirts

5j + 2s = $207

3j + 4s = $169

System of equations. You now must choose to either cancel out "j" or "s".

I'm going to cancel out the "s".

In order to cancel out the "s" you must make the number in front of each s the same number, but opposite. Meaning one is negative, and the other is positive.

2s and 4s. You can get 2 to 4 by multiplying by 2. And you want it to be negative. So you'll be multiplying the ENTIRE top equation by -2.

-2(5j+2s=207)

-2 x 5j = -10j

-2 x 2s = -4s

-2 x 207 = -414.

Rewrite the equation.

-10j - 4s = -414.

3j + 4s = 169.

You can now cancel out the "s"'s by adding them together. -4 + 4 = 0.

Now, you must add the other numbers, both "j"s and both of the totals.

-10j + 3j = -7j.

-414 + 169 = -245.

Put those numbers back into the equation..

-7j = - 245.

Divide both sides by -7 to get j by itself.

j = 35; each pair of jeans is worth $35.

Now, solve for "s" by plugging the value of j (35) into either of the ORGINAL equations. (5j + 2s = $207 OR 3j + 4s = $169)

5j + 2s = 207.

5(35) + 2s = 207.

175 + 2s = 207

Subtract 175 from both sides.

2s = 32

Divide both sides by 2.

s = 16; each sweatshirt costs $16.

5 0

3 years ago

Read 2 more answers

I can’t figure out how to use the zeros in the polynomial. Please explain

Temka [501]

Answer:

a) $P (x) = (x + 3) (x-1) (x-4)$

b) $P (x) = (2x + 5) (5x - 4) (x-6)$

c) $P (x) = (x-3) (x-1) (x-4) (x + 1) ^ 2$

Step-by-step explanation:

For the question a * you need to find a polynomial of degree 3 with zeros in -3, 1 and 4.

This means that the polynomial P(x) must be zero when x = -3, x = 1 and x = 4.

Then write the polynomial in factored form.

$P (x) = (x + 3) (x-1) (x-4)$

Note that this polynomial has degree 3 and is zero at x = -3, x = 1 and x = 4.

For question b, do the same procedure.

Degree: 3

Zeros: -5/2, 4/5, 6.

The factors are

$x = -\frac{5}{2}\\\\x +\frac{5}{2} = 0\\\\(2x +5) = 0$

---------------------------------------

$x =\frac{4}{5}\\\\x-\frac{4}{5} = 0\\\\(5x-4) = 0$

--------------------------------------

$x = 6\\\\(x-6) = 0$

--------------------------------------

$P (x) = (2x + 5) (5x - 4) (x-6)$

Finally for the question c we have

Degree: 5

Zeros: -3, 1, 4, -1

Multiplicity 2 in -1

$x = -3\\\\(x-3) = 0$

--------------------------------------

$x = 1\\\\(x-1) = 0$

--------------------------------------

$x = 4\\\\(x-4) = 0$

----------------------------------------

$x = -1\\\\(x + 1) = 0$

-----------------------------------------

$P (x) = (x-3) (x-1) (x-4) (x + 1) ^ 2$

8 0

2 years ago

Sociologists say the percentage of the classic music lovers is about 5%. From the survey, we know that only 83 out of 2000 peopl

disa [49]

Answer:

p value from chi square = 0.081

Step-by-step explanation:

Given that sociologists say the percentage of the classic music lovers is about 5%. From the survey, we know that only 83 out of 2000 people listen to the classic music. Let denote the proportion of the classic music lovers. The hypotheses are H0: p=0.05 vs Ha: p≠0.05

p value = 0.09

Instead of this if we do chi square

H0: Proportion of music lovers is 5% and non music lovers is 95%

Ha: Proportions are not as per the estimate

(Two tailed chi square test)

Observed 83 1917 2000

Expected 100 1900 2000

O-E -17 17 0

chi square

(O-E)^2/E 2.89 0.1521 3.0421

df =1

p value from chi square = 0.081

Though p value is not exactly the same, the conclusion in both tests are the same

5 0

3 years ago

Is the number 15 prime or composite? A. prime B. composite

34kurt

Hello there.

Is the number 15 prime or composite?

Answer: Composite

8 0

2 years ago

Read 2 more answers