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alexandr1967 [171]
3 years ago
5

Need help on a systems of equations word problem

Mathematics
1 answer:
lapo4ka [179]3 years ago
8 0

Answer:

brazil: 12.8 portugal: 14.769230769230769 (you need to round it)  

Step-by-step explanation:

just divide.

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Write each expression as a product of linear factors 1. X^2+1/2x 2. X^2+2x-3 3. (2x-3)^2 4. X^3+2x^2-19x-20
Grace [21]

Answer:

1. X^2+1/2x = x(x+\frac{1}{2})

2.  X^2+2x-3 = (x-1)(x+3)

3. (2x-3)^2 = (2x-3)(2x-3)

4. X^3+2x^2-19x-20 = (x+1)(x-4)(x+5)

Step-by-step explanation:

Each expression can be written as a product of linear factors as follows

1. X^2+1/2x ⇒ x^{2} + \frac{1}{2}x

x^{2} + \frac{1}{2}x = x(x+\frac{1}{2})

Hence,  X^2+1/2x = x(x+\frac{1}{2})

2. X^2+2x-3 ⇒ x^{2} +2x-3

x^{2} +2x-3 = x^{2} +3x-x-3

x^{2} +3x-x-3 = x(x+3) -1(x+3)

x(x+3) -1(x+3) = (x-1)(x+3)

Hence,  X^2+2x-3 = (x-1)(x+3)

3. (2x-3)^2 ⇒(2x-3)^{2}

(2x-3)^{2} = (2x-3)(2x-3)

Hence, (2x-3)^2 = (2x-3)(2x-3)

4. X^3+2x^2-19x-20 ⇒ x^{3}+2x^{2} -19x -20

x^{3}+2x^{2} -19x -20  = (x+1)(x^{2} +x-20)

First,

x^{2} +x-20 = x^{2} +5x-4x-20\\x^{2} +5x-4x-20= x(x+5)-4(x+5)\\x(x+5)-4(x+5) = (x-4)(x+5)

∴ (x+1)(x^{2} +x-20) = (x+1)(x-4)(x+5)

Hence, X^3+2x^2-19x-20 = (x+1)(x-4)(x+5)

3 0
3 years ago
In a certain population, body weights are normally distributed with a mean of 152 pounds 30) and a standard deviation of 26 poun
Paul [167]

We are given the following variables:

μ = the sample mean = 152 pounds

σ = the standard deviation = 26 pounds

x = the sample value we want to test = 180 pounds

n = the sample size = unknown

MOE = margin of error = 4% = 0.04

Confidence level = 96%

 

The first thing we can do is to find for the value of z using the formula:

z = (x – μ) / σ

z = (180 – 152) / 26

z = 1.0769 = 1.08

Since we are looking for the people who weigh more than 180 pounds, therefore this is a right tailed z test. The p value is:

p = 0.1401

 

Then we can use the formula below to solve for n:

n = z^2 * p * (1 – p) / (MOE)^2

n = 1.08^2 * 0.1401 * (1 – 0.1401) / (0.04)^2

n = 87.82 = 88

 

Therefore around 88 people must be surveyed.

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3 years ago
A community college has 2,000 students and 50 instructors. Next year the enrollment will be 6,000. How many new instructors shou
juin [17]
\begin{array}{ccc}2,000&-&50\\\\6,000&-&x\end{array}\\\\\\2,000x=50\times6,000\ \ \ \ \ /:2,000\\\\x=\frac{300,000}{2,000}\\\\x=150\\\\150-50=100\\\\Answer:100\ new\ instructors.
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3 years ago
A 30-60-90 triangle with a hypotenuse of 6 . Find the length of all other sides
andrew-mc [135]
1.  Find the "opposite side," if the angle is 60 degrees and the hyp is 6:
     
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      sin 60 deg = ------- = -------- = ----------
                            hyp          6             2

      Cross-multiplying, 2(opp) = 6sqrt(3), so that opp = 3 sqrt(3) (answer)

2.  Use the Pyth. Thm. to find the "adjacent side:"

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The lengths of the legs of this 30-60-90 triangle are 3 and 3 sqrt(3).

check:  Does 3^2 + [3sqrt(3)]^2 = 6^2?
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3 years ago
add or subtract the fractions for the addition problems write another addition problem that has the same sum and use two or more
lesya692 [45]
You can add these fractions to get 9/12 - 2/12 ( 7/12 )

3/12 + 4/12
1/12 + 6/12
2/12 + 5/12

6 0
3 years ago
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