I am going to explain this using the substitution method, considering it appears to be the best in this situation.

We know (from the bottom equation) that y can equal 3x+20. Using this knowledge, we substitute the y in the top equation for 3x+20. Now, we have an equation that looks like this:

3x+20=x^2+2x

Now we need to move x to one side and then do some radicals (square roots).
Subtract the 2x on the right (since it is smaller, negatives = NONONO), which will give you

x+20=x^2

Now, we take the square root of both sides to get

rad(x+20)=x

Now we have to simplify. 20 doesn't have a square root, but 4 goes into 20, and 4 has a square root of 2. This now becomes

2rad(x+5)

This doesn't simplify any further... we have a problem... no way to isolate x as far as my knowledge goes... Sorry, can't help you any further than that, but another person or your teacher might be able to. R.I.P...

4 0

3 years ago

In a class of p students, the average (arithmetic mean) of the test scores is 70. in another class of n students, the average of

lys-0071 [83]

First case:

average of test score =70

number of students =p

total score of 'p' students = ( average of test score)*( number of students)

total score of 'p' students =70p

Second case:

average of test score =92

number of students =n

total score of 'n' students = ( average of test score)*( number of students)

total score of 'n' students =92n

total number of students = p+n

total average score =86

so, total score =86(p+n)

total score = total score of 'p' students +total score of 'n' students

$86(p+n)=70p+92n$

now, we can simplify it

$86p+86n=70p+92n$

$86p-70p=92n-86n$

$16p=6n$

now, we can find p/n

$\frac{p}{n}= \frac{6}{16}$

$\frac{p}{n}= \frac{3}{8}$ ................Answer

5 0

3 years ago

Find the slope of the line given two points:

vesna_86 [32]

Answer:

<h3>The answer is option C</h3>

Step-by-step explanation:

The slope of a line given two points can be found by using the formula

$m = \frac{ y_2 - y _ 1}{x_ 2 - x_ 1} \\$

where

(x1 , y1) and (x2 , y2) are the points

From the question the points are

(8, 10) and (-7, 14)

The slope is

$m = \frac{14 - 10}{ - 7 - 8} = \frac{4}{ - 15} = - \frac{4}{15} \\$

We have the final answer as

$- \frac{4}{15} \\$

Hope this helps you

4 0

3 years ago

What equation this show<br> The cost of 10 pounds of potatoes is 8 dollars

Alekssandra [29.7K]

To formulate the equation that shows the cost of 10 pounds of potatoes is 8 dollars we proceed as follows;
suppose the cost 1 pound is x;
thus,
total cost=(amount in pounds)*(price of one pound)
total cost=$8
amount=10 pounds
cost of one pound=x
thus the equation is;
8=10x

8 0

3 years ago