Answer:
Step-by-step explanation:
85-x=100
85 represents sarah's hw
x represent Emily's hw
100 represents total completion
Step-by-step explanation:
(-3y^2+24y)(-6y^2-3y)
open the bracket and collect the like terms
-3y^2-6y^2+24y-3y
-9y^2+21y
Answer:
a
The average cost is 
b
The standard deviation of cost is
Step-by-step explanation:
From the question we are told that




The cost of replacing the two component is C = 50 + 2 X + 4 Y
The variance of X is mathematically represented as
V(X) =
Substituting values
![V[X] = 24 - 4^2](https://tex.z-dn.net/?f=V%5BX%5D%20%3D%20%2024%20-%204%5E2)
![V[X] =8](https://tex.z-dn.net/?f=V%5BX%5D%20%3D8)
The variance of Y is mathematically represented as
V(Y) =
Substituting values
![V[Y] = 8 - 2^2](https://tex.z-dn.net/?f=V%5BY%5D%20%3D%20%208%20-%202%5E2)
![V[X] =4](https://tex.z-dn.net/?f=V%5BX%5D%20%3D4)
The average of replacing the two component is

substituting value


The variance of replacing the two component is
Note: The variance of constant is zero
and X and Y are independent
=> 
substituting values
=>
=>
=> 
The standard deviation is
substituting values
All you do is change signs write 2x minus 14 equals negative 10-14 equals four then you write 2x over two equals four over two then u write x equals negative two