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svetoff [14.1K]
2 years ago
14

I need help with number 4!

Mathematics
2 answers:
irina1246 [14]2 years ago
7 0
X is -8 and Y is 6 I hoped this helps!
lesya692 [45]2 years ago
5 0

Answer:

x = -8, y = 6

Step-by-step explanation:

x + 2y = 4 ------(1)

x + y = - 2

y = - x - 2 ----------(2)

Substitute y in (1)

x + 2(- x - 2) = 4

x - 2x - 4 = 4

- x = 4 + 4

x = -8

Substitute x in (2)

y = - (- 8) - 2 = 8 - 2 = 6

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Find the reciprocal 8
love history [14]
-1/8  is your answer

hope this helps
8 0
3 years ago
Suppose that X is a random variable with mean 30 and standard deviation 4. Also suppose that Y is a random variable with mean 50
Vladimir79 [104]

Answer:

a) Var[z] = 1600

    D[z] = 40

b) Var[z] = 2304

    D[z] = 48

c) Var[z] = 80

    D[z] = 8.94

d) Var[z] = 80

    D[z] = 8.94

e) Var[z] = 320

    D[z] = 17.88

Step-by-step explanation:

In general

V([x+y] = V[x] + V[y] +2Cov[xy]

how in this problem Cov[XY] = 0, then

V[x+y] = V[x] + V[y]

Also we must use this properti of the variance  

V[ax+b] = a^{2}V[x]

and remember that

standard desviation = \sqrt{Var[x]}

a) z = 35-10x

   Var[z] = 10^{2} Var[x] = 100*16 = 1600

   D[z] = \sqrt{1600} = 40

b) z = 12x -5

   Var[z] = 12^{2} Var[x] = 144*16 = 2304

   D[z] = \sqrt{2304} = 48

c) z = x + y

   Var[z] =  Var[x+y] = Var[x] + Var[y] = 16 + 64 = 80

   D[z] = \sqrt{80} = 8.94  

d) z = x - y

   Var[z] =  Var[x-y] = Var[x] + Var[y] = 16 + 64 = 80

   D[z] = \sqrt{80} = 8.94

e) z = -2x + 2y

   Var[z] = 4Var[x] + 4Var[y] = 4*16 + 4*64 = 320

  D[z] = \sqrt{320} = 17.88

   

7 0
3 years ago
Find the average value of f over region
yan [13]
The area of D is given by:

\int\limits \int\limits {1} \, dA = \int\limits_0^7 \int\limits_0^{x^2} {1} \, dydx  \\  \\ = \int\limits^7_0 {x^2} \, dx =\left. \frac{x^3}{3} \right|_0^7= \frac{343}{3}

The average value of f over D is given by:

\frac{1}{ \frac{343}{3} }  \int\limits^7_0  \int\limits^{x^2}_0 {4x\sin(y)} \, dydx  = -\frac{3}{343}  \int\limits^7_0 {4x\cos(x^2)} \, dx  \\  \\ =-\frac{3}{343} \int\limits^{49}_0 {2\cos(t)} \, dt=-\frac{6}{343} \left[\sin(t)\right]_0^{49} \, dt=-\frac{6}{343}\sin49
3 0
3 years ago
Can someone help me ASAP
sammy [17]

Answer:

8/9 n-3

Step-by-step explanation:

5 0
3 years ago
Read 2 more answers
3x - 2y = -18 use the table of vaules to graph the line
docker41 [41]

Answer:

Given the equation of line :  3x -2y = -18

Table values:

x                  y

0                  9

2                  12

4                   15

6                   18

-6                  0

Now, plot these points (0,9), (2, 12), (4, 15) , (6, 18) and (-6, 0) on the co-ordinate planer, to graph the the line.

You can see the graph of the given equation as shown below.                  

3 0
3 years ago
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