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3 years ago

PLEASE HELP ME IM IN DESPERATE NEED OF THE ANSWER

Mathematics

1 answer:

eduard3 years ago

6 0

Answer:

a) x= -3 y=0

x= -2 y=8

x= -1 y=6

x= 0 y=0

x= 1 y= -4

x= 2 y= 0

x= 3 y= 18

b) x³ + x² - 6x=0

x* (x² + x -6)=0

x( x(x-2) +3(x-2))=0

x=0

x-2=0 x=2

x+3=0 x= -3

x= 0, x=2, x=-3

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Simplify! (a^3b)(abc) A) a^2bc^5 B) a^4b^2 C) a^4b^2c D) a^4bc

fenix001 [56]

Answer:

$a^{3}$ *b*(abc)= $a^{4} * b^{2} * c$

Step-by-step explanation:

you use the distributive property

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2 years ago

Read 2 more answers

SAT scores are normed so that, in any year, the mean of the verbal or math test should be 500 and the standard deviation 100. as

vovangra [49]

Answer:

a) $P(X>625)=P(\frac{X-\mu}{\sigma}>\frac{625-\mu}{\sigma})=P(Z>\frac{625-500}{100})=P(Z>1.25)$

$P(Z>1.25)=1-P(Z$

b) $P(400$

$P(-1$

c) $z=-0.842$

And if we solve for a we got

$a=500 -0.842*100=415.8$

So the value of height that separates the bottom 20% of data from the top 80% is 415.8.

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Part a

Let X the random variable that represent the SAT scores of a population, and for this case we know the distribution for X is given by:

$X \sim N(500,100)$

Where $\mu=500$ and $\sigma=100$

We are interested on this probability

$P(X>625)$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(X>625)=P(\frac{X-\mu}{\sigma}>\frac{625-\mu}{\sigma})=P(Z>\frac{625-500}{100})=P(Z>1.25)$

And we can find this probability using the complement rule and with the normal standard table or excel:

$P(Z>1.25)=1-P(Z$

Part b

We are interested on this probability

$P(400$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

If we apply this formula to our probability we got this:

$P(400$

And we can find this probability with this difference:

$P(-1$

And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.

$P(-1$

Part c

For this part we want to find a value a, such that we satisfy this condition:

$P(X>a)=0.8$ (a)

$P(X$ (b)

Both conditions are equivalent on this case. We can use the z score again in order to find the value a.

As we can see on the figure attached the z value that satisfy the condition with 0.2 of the area on the left and 0.8 of the area on the right it's z=-0.842. On this case P(Z<-0.842)=0.2 and P(Z>-0.842)=0.8

If we use condition (b) from previous we have this:

$P(X$

$P(z$

But we know which value of z satisfy the previous equation so then we can do this:

$z=-0.842$

And if we solve for a we got

$a=500 -0.842*100=415.8$

So the value of height that separates the bottom 20% of data from the top 80% is 415.8.

8 0

2 years ago

NO LINKS!!

yan [13]

Answer:

$y=-\dfrac{1}{2}(x+4)^2-1$

Step-by-step explanation:

Vertex form: $y=a(x-h)^2+k$

where:

$(h, k)$ is the vertex
$a$ is some constant

Given:

vertex = (-4, -1)
point on parabola = (-2, -3)

Substitute given values into the formula to find $a$ :

$\implies -3=a((-2)-(-4))^2+(-1)$

$\implies -3=a(2)^2-1$

$\implies -3=4a-1$

$\implies -2=4a$

$\implies a=-\dfrac{2}{4}=-\dfrac{1}{2}$

Therefore, the equation of the parabola is:

$y=-\dfrac{1}{2}(x+4)^2-1$

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What expression is equivalent to 2.2-2.5?

Pani-rosa [81]

Hi Camrynb10705oxknsv!
So let's take a look at the answers they give. A is 2.5 - 2.2 and all that is is switching the numbers so that isn't right. B they do addition instead of subtraction so that can't be right. C they do 2.2 + (-2.5) and when you add a negative number it's like subtraction because a negative number is under 0 and so your adding a number under 0 so you go down. So the answer is C.
If you need me to explain it different let me know. Hope this helps!

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Helen [10]

Answer:

Step-by-step explanation:

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3 years ago