1. |x+5|=3 How do I get this again?

(a + b - c )(a + b + c )

denis-greek [22]

Answer:

$a^2+b^2-c^2+2ab$

Step-by-step explanation:

$(a+b-c)(a+b+c)=a^2+ab+ac+ab+b^2+bc-ac-bc-c^2=a^2+b^2-c^2+2ab$

Hope this helps!

5 0

2 years ago

Read 2 more answers

I need help please explain your work for number 7 only

Keith_Richards [23]

Answer:

Transitive property

Step-by-step explanation:

When a=c and b=c, a=b

A would be 16+43

B would be 59

C would be 10+49

5 0

1 year ago

Please help and explain!

Scrat [10]

K is the slope of the line formed by connecting the points.
Use slope formula:
$\frac{y_2 - y_1}{x_2 - x_1}$
where the 2 points are the end points of the line (First and last going Left to right)
$(x_1,y_1) = (2,7) \\ (x_2,y_2) = (8,28)$
Substitute into slope formula
$k= \frac{28-7}{8-2} = \frac{21}{6} = \frac{7}{2}$
You can check if this is correct by going back to graph and going "up 7" and "over 2" to get from one point to the next.

5 0

3 years ago

Malik collects rare stamps and has a total of 212 stamps. He has 34 more domestic stamps than foreign stamps. Let x represent th

Effectus [21]

Answer:

y = 89 x = 123

Step-by-step explanation:

since they're both in standard form, its easier to do the process of elimination

x - y = 34

-x -y -212

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

-2y = -178

y = 89

now plug in y to any one of those two equations

x - y = 34

x - 89 = 34

x = 123

to check:

x + y = 212

123 + 89 = 212

212 = 212

6 0

2 years ago

A recent survey based on a random sample of n=470 voters, predicted that independent candidate for the mayoral election will get

julsineya [31]

I have an expression

$\sigma = \sqrt{p(1-p)/n}$

floating around in my head; let's see if it makes sense.

The variance of binary valued random variable b that comes up 1 with probability p (so has mean p) is

$E( (b-p)^2 ) = (-p)^2(1-p) + (1-p)^2p = p(1-p)$

That's for an individual sample. For the observed average we divide by n, and for the standard deviation we take the square root:

$\sigma = \sqrt{p(1-p)/n}$

Plugging in the numbers,

$\sigma = \sqrt{.24(1-.24)/490} = 0.019 = 1.9\%$

One standard deviation of the average is almost 2% so a 27% outcome was 3/1.9 = 1.6 standard deviations from the mean, corresponding to a two sided probability of a bit bigger than 10% of happening by chance.

So this is borderline suspect; most surveys will include a two sigma margin of error, say plus or minus 4 percent here, and the results were within those bounds.

7 0

3 years ago