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3 years ago

R’(-1, 9) is the image of R after a reflection in the x-axis. What are the coordinates of R?

Mathematics

1 answer:

xz_007 [3.2K]3 years ago

6 0

Answer:

Step-by-step explanation:

When we reflect over x-axis then the x-coordinate doesn't change and the y-coordinate changes its sign

in means if R = (x, y) then R' = (x, -y)

so we have:

x = -1 and -y = 9

y = -9

which gives R = (-1, -9)

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(4x + 4) (5x + 2) =

kirill115 [55]

Answer:

Step-by-step explanation:

20x^2+28x+8

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3 years ago

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assume that when adults with smartphones are randomly selected 15 use them in meetings or classes if 15 adult smartphones are ra

Tanzania [10]

Answer:

The probability that at least 4 of them use their smartphones is 0.1773.

Step-by-step explanation:

We are given that when adults with smartphones are randomly selected 15% use them in meetings or classes.

Also, 15 adult smartphones are randomly selected.

Let X = <em>Number of adults who use their smartphones</em>

The above situation can be represented through the binomial distribution;

$P(X = r) = \binom{n}{r}\times p^{r} \times (1-p)^{n-r} ; n = 0,1,2,3,.......$

where, n = number of trials (samples) taken = 15 adult smartphones

r = number of success = at least 4

p = probability of success which in our question is the % of adults

who use them in meetings or classes, i.e. 15%.

So, X ~ Binom(n = 15, p = 0.15)

Now, the probability that at least 4 of them use their smartphones is given by = P(X $\geq$ 4)

P(X $\geq$ 4) = 1 - P(X = 0) - P(X = 1) - P(X = 2) - P(X = 3)

= $1- \binom{15}{0}\times 0.15^{0} \times (1-0.15)^{15-0}-\binom{15}{1}\times 0.15^{1} \times (1-0.15)^{15-1}-\binom{15}{2}\times 0.15^{2} \times (1-0.15)^{15-2}-\binom{15}{3}\times 0.15^{3} \times (1-0.15)^{15-3}$

= $1- (1\times 1\times 0.85^{15})-(15\times 0.15^{1} \times 0.85^{14})-(105 \times 0.15^{2} \times 0.85^{13})-(455 \times 0.15^{3} \times 0.85^{12})$

= <u>0.1773</u>

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3 years ago

Math zoom join ends at 10:30 ID: 854 8913 6878<br> PASSCODE: 8yw2id hurry join be funny

Inessa05 [86]

no thanks but I'll see if I can get friends to join

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Cuánto es la ecuación 5x +6 =21

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Answer:

x=3

Step-by-step explanation:

5x+6=21

5x=15

x=3

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2 years ago

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find the equation of the sides of an isosceles right angled triangle whose vertex is (-2,-3) and the base is on the line x=0

Serggg [28]

Answer:

AC:y=x-1 CB:y=-x-5 AB:x=0

Step-by-step explanation:

Consider the triangle. The base AB is on the line x=0, the vertex C is (-2,-3)

The side AC is equal to BC. The angle ACB is 90 degrees. If the base is on the line x=o, it is on the axis Y.Explore the distance from the point C to the AB

c(-2,-3), the distance to the axis Y is equal to the modul of the coordinate x (-2), it is 2. The coordinates of point projected by the point C to the axis Y is N(0,-3). The modul of the height is 2, the height of the isosceles triangle to the base is the bisectrix, so the angle BCA is 90/2=45degrees, CBA is 180-90-45=45 degrees too

the heigt CN is equal to side NB, NB=2

Suppose B is (0,y) (x=0 because the base is on this line)

THe modul of the vector NB is equal to sqrt ((0-0)^2+(y+3)^2)= 2

modul (y+3)= 2

y=-1 or y=-5

(0,-1), (0,-5) - two points, one of them (suppose B) is (0,-5) when A is (0,-1) (A is remote from the point N on the same distance with B, because AB is the median too)

Find CB and AC

Use the equation for AC

(x-0)/(-2-0)= (y+1)/(-3+1)

x/-2= (y+1)/-2

x=y+1

y=x-1

For CB

(x-0)/ (-2-0)= (y+5)/ (-3-(-5))

x/-2= (y+5)/2

-x=y+5

y=-x-5

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