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] = 
V[x]
and remember that
standard desviation = ![\sqrt{Var[x]}](https://tex.z-dn.net/?f=%5Csqrt%7BVar%5Bx%5D%7D)
a) z = 35-10x
Var[z] = 
Var[x] = 100*16 = 1600
D[z] = 
= 40
b) z = 12x -5
Var[z] = 
Var[x] = 144*16 = 2304
D[z] = 
= 48
c) z = x + y
Var[z] = Var[x+y] = Var[x] + Var[y] = 16 + 64 = 80
D[z] = 
= 8.94
d) z = x - y
Var[z] = Var[x-y] = Var[x] + Var[y] = 16 + 64 = 80
D[z] = = 8.94
e) z = -2x + 2y
Var[z] = 4Var[x] + 4Var[y] = 4*16 + 4*64 = 320
D[z] = 
= 17.88
Answer:
x = 4
Step-by-step explanation:
All of the sides are the same so every angle is 17x-8.
Every triangle adds up to 180 degrees.
3(17x-8)=180
51x-24=180
+24 +24
51x=204
x= 4
Step-by-step explanation:
let's assume one month is 30 days you would multiply 10 by 30.
which would be 300 hours in 1 month
now if one month is 31 days you would simply multiply 10 by 31.
which would be 310 hours
-2x^2 + 3x - 9 = 0
The quadratic is not factorable so quadratic formula must be used.
x = (-b + - √(b^2 - 4ac))/2a
a = -2, b = 3, c = -9
x = (-3 + - √(9 - 4*-2*-9))/-4
x = (-3 + - √(-63))/-4
x = -3 + - 3i√7
--------------
-4
x = 3 + 3i√7 x = 3 - 3i√7
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4 4
Joseph Pulitzer
Rough Riders
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