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2 years ago

What is the image of the point (-7,9) after a rotation of 270 counterclockwise about the origin

1 answer:

8 0

Answer is (9, 7)

Step by step

Rule: 270 degrees counterclockwise about the origin our point A(x,y) becomes A'(y,-x).

This means, we switch x and y and make x negative.

So

(-7, 9) ➡️ ( 9, 7)

You might be interested in

Find the perimeter of the rectangle whose lenth is 24cm and diagonal is 25cm

Ahat [919]

P=2l +2w to find w use Pythagorean theorem

25^2 -24^2= w^2
625-576=w^2
w=7
2l +2w: l=24 w=7
24+24+7+7=62
Perimeter=62 cm

3 0

4 years ago

A particular concentration of a chemical found in polluted water has been found to be lethal to 20% of the fish that are exposed

torisob [31]

Answer:

a) $P(X=14)=(20C14)(0.8)^{14} (1-0.8)^{20-14}=0.109$

b) $P(X\geq 10) = 1-P(X \leq 9) = 0.9994$

c) $P(X \leq 16)= 1-P(X>16) =1-P(X \geq 17)= 1- [P(X=17) +...+P(X=20)]=0.589$

d) $E(X)= np = 20 *0.8 = 16$

$Var(X) = np(1-p) = 20*0.8*(1-0.8) = 3.2$

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=20, p=1-0.2=0.8)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

Part a

For this case we want this probability:

$P(X=14)$

And using the mass function we have this:

$P(X=14)=(20C14)(0.8)^{14} (1-0.8)^{20-14}=0.109$

Part b

For this case we want this probability:

$P(X \geq 10)$

And we can find this using the complement rule:

$P(X\geq 10) = 1-P(X$

$P(X=0)=(20C0)(0.8)^{0} (1-0.8)^{20-0}=1.05x10^{-14}$

$P(X=1)=(20C1)(0.8)^{1} (1-0.8)^{20-1}=8.39x10^{-13}$

$P(X=2)=(20C2)(0.8)^{2} (1-0.8)^{20-2}=3.19x10^{-11}$

$P(X=3)=(20C3)(0.8)^{3} (1-0.8)^{20-3}=7.65x10^{-10}$

$P(X=4)=(20C4)(0.8)^{4} (1-0.8)^{20-4}=1.30x10^{-8}$

$P(X=5)=(20C5)(0.8)^{5} (1-0.8)^{20-5}=1.66x10^{-7}$

$P(X=6)=(20C6)(0.8)^{6} (1-0.8)^{20-6}=1.66x10^{-6}$

$P(X=7)=(20C7)(0.8)^{7} (1-0.8)^{20-7}=1.33x10^{-5}$

$P(X=8)=(20C8)(0.8)^{8} (1-0.8)^{20-8}=8.65x10^{-5}$

$P(X=9)=(20C9)(0.8)^{9} (1-0.8)^{20-9}=0.00046$

And if we replace we got:

$P(X\geq 10) = 1-P(X \leq 9) = 0.9994$

Part c

For this case we want this probability:

$P(X \leq 16)$

And we can use the complement rule like this:

$P(X \leq 16)= 1-P(X>16) =1-P(X \geq 17)= 1- [P(X=17) +...+P(X=20)]$

$P(X=17)=(20C17)(0.8)^{17} (1-0.8)^{20-17}=0.205$

$P(X=18)=(20C18)(0.8)^{18} (1-0.8)^{20-18}=0.137$

$P(X=19)=(20C19)(0.8)^{19} (1-0.8)^{20-19}=0.0576$

$P(X=20)=(20C20)(0.8)^{20} (1-0.8)^{20-20}=0.0115$

And if we replace we got:

$P(X \leq 16)= 1-P(X>16) =1-P(X \geq 17)= 1- [P(X=17) +...+P(X=20)]=0.589$

Part d

The expected value is given by:

$E(X)= np = 20 *0.8 = 16$

$Var(X) = np(1-p) = 20*0.8*(1-0.8) = 3.2$

3 0

3 years ago

What is the measure of ∠XBC?

bija089 [108]

The measure of an exterior angle of triangle is equal to the sum of measures of two interior angles of triangle that are not supplementary with this exterior angles.

In the case of this question this fact sounds as

m∠XBC = m∠BAC + m∠BCA (option 1).

Now if

m∠XBC=(3p-6)°
m∠BAC=(p+4)°
m∠BCA=84°,

then

3p-6=p+4+84 (option 2),

3p-6=p+88 (option 3),

3p-p-6=p-p+88,

2p-6=88 (option 4),

2p-6+6=88+6,

2p=94 (option 5),

p=47.

Then m∠XBC=(3p-6)°=(3·47-6)°=135°.

Answer: m∠XBC=135°.

8 0

3 years ago

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BRAINLIEST<br><br>determine if each function is linear or nonlinear

Karo-lina-s [1.5K]

Answer:

#1- linear

#2- linear

#3- linear

#4- nonlinear

Step-by-step explanation:

A system of nonlinear equations is a system of two or more equations in two or more variables containing at least one equation that is not linear. A linear equation looks like any other equation. It is made up of two expressions set equal to each other. A non linear looks like a u shape when graphed and a linear equation looks like a diagonal or straight line when graphed.

this site can help too: desmos graphing calculator

3 0

3 years ago

98 POINTS FOR IMMEDIATE HELP. I'VE TRIED JUST THE FIRST TWO AND IT WASN'T CORRECT.

elena55 [62]

Answer:

two pair of opposite parallel sides

two pair of opposite congruent angles

i am sorry if i was wrong but thoes are the only reasonable answers

4 0

3 years ago

Read 2 more answers