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2 years ago

How to do 2/5 = (x-3)/(7x+15)

Mathematics

2 answers:

Zigmanuir [339]2 years ago

6 0

Answer:

$x = - 5$

Step-by-step explanation:

To work out this question you have to first cross multiply.

$\frac{2}{5} = \frac{(x - 3)} {(7x + 15)} \\ \\ 2(7x + 15) = 5(x - 3)$

When you cross multiply you will get the equation above. Therefore

$(2 \times 7x) + (2 \times 15) = (5 \times x) \\ - (5 \times 3) \\ \\ 14x + 30 = 5x - 15 \\ \\ 14x - 5x = - 30 - 15 \\ \\ 9x = - 45$

Therefore

$\frac{9}{9} x = \frac{ - 45}{9} \\ \\ x = - 5$

Serggg [28]2 years ago

3 0

Answer:

x = -5

Step by step:

multiply both side by 7x + 15.

2/5 (7x+15)= x − 3

Simplify 2)5 (7x+15) to 2(7x+15)/5.

2(7x+15)/5= x - 3

multiply both sides by 5.

2(7x+15)= 5x - 15

Expand.

14x+30= 5x - 15

subtract 5x from both sides.

14x+30−5x= − 15

Simplify 14x + 30 - 5x14x + 30−5x to 9x + 309x + 30.

9x+30= - 15

Subtract 30 from both sides.

simplify

x = -5

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chubhunter [2.5K]

Y - 10 =(-1/3) ( X - 10 )

Y = ( -1/3) X + ( 40/3)

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Step 1:

The basic form of Slope Intercept equation is

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3 years ago

A certain genetic condition affects 8% of the population in a city of 10,000. Suppose there is a test for the condition that has

enot [183]

Solution:

Population in the city= 10,000

As genetic condition affects 8% of the population.

8 % of 10,000

$=\frac{8}{100}\times 10,000=800$

As, it is also given that, there is an error rate of 1% for condition (i.e., 1% false negatives and 1% false positives).

So, 1% false negatives means out of 800 tested who are found affected , means there are chances that 1% who was found affected are not affected at all.

So, 1% of 800 $=\frac{1}{100}\times 800=8$

Also, 1% false positives means out of 10,000 tested,[10,000-800= 9200] who are found not affected , means there are chances that 1% who was found not affected can be affected also.

So, 1% of 9200 $=\frac{1}{100}\times 9200=92$

1. Has condition Does not have condition totals = 800

2. Test positive =92

3. Test negative =8

4. Total =800 +92 +8=900

5. Probability (as a percentage) that a person has the condition if he or she tests positive= As 8% are found positive among 10,000 means 9200 are not found affected.But there are chances that out of 9200 , 1% may be affected

$=\frac{\text{1 percent of 9200}}{9200}\\\\ \frac{\frac{1}{100}\times 9200}{9200}=\frac{92}{9200}\\\\ =0.01$