Answer:
Answer: 9 (y - 2) (y + 2)
Step-by-step explanation:
Factor the following:
9 y^2 - 36
Factor 9 out of 9 y^2 - 36:
9 (y^2 - 4)
y^2 - 4 = y^2 - 2^2:
9 (y^2 - 2^2)
Factor the difference of two squares. y^2 - 2^2 = (y - 2) (y + 2):
Answer: 9 (y - 2) (y + 2)
Answer:
C. x+5
Step-by-step explanation:
Quotient is the result obtained by dividing one number by the other. Polynomial is the equation which consists of variables and coefficients. It involves addition, subtraction, multiplication and integers. The given synthetic equation is 2/1 5 - 14. In the given equation the quotient polynomial form is x + 5.
By definition of covariance,
![\mathrm{Cov}(X,Y)=\mathbb E[(X-\mathbb E[X])(Y-\mathbb E[Y])]](https://tex.z-dn.net/?f=%5Cmathrm%7BCov%7D%28X%2CY%29%3D%5Cmathbb%20E%5B%28X-%5Cmathbb%20E%5BX%5D%29%28Y-%5Cmathbb%20E%5BY%5D%29%5D)
![\mathrm{Cov}(X,Y)=\mathbb E[XY-\mathbb E[X]Y-X\mathbb E[Y]+\mathbb E[X]\mathbb E[Y]]=\mathbb E[XY]-\mathbb E[X]\mathbb E[Y]](https://tex.z-dn.net/?f=%5Cmathrm%7BCov%7D%28X%2CY%29%3D%5Cmathbb%20E%5BXY-%5Cmathbb%20E%5BX%5DY-X%5Cmathbb%20E%5BY%5D%2B%5Cmathbb%20E%5BX%5D%5Cmathbb%20E%5BY%5D%5D%3D%5Cmathbb%20E%5BXY%5D-%5Cmathbb%20E%5BX%5D%5Cmathbb%20E%5BY%5D)
We have
![\mathbb E[(aX-b)(cY-d)]=\mathbb E[acXY-adX-bcY+bd]](https://tex.z-dn.net/?f=%5Cmathbb%20E%5B%28aX-b%29%28cY-d%29%5D%3D%5Cmathbb%20E%5BacXY-adX-bcY%2Bbd%5D)
![=ac\mathbb E[XY]-ad\mathbb E[X]-bc\mathbb E[Y]+bd](https://tex.z-dn.net/?f=%3Dac%5Cmathbb%20E%5BXY%5D-ad%5Cmathbb%20E%5BX%5D-bc%5Cmathbb%20E%5BY%5D%2Bbd)
![\mathbb E[aX-b]=a\mathbb E[X]-b](https://tex.z-dn.net/?f=%5Cmathbb%20E%5BaX-b%5D%3Da%5Cmathbb%20E%5BX%5D-b)
![\mathbb E[cY-d]=c\mathbb E[Y]-d](https://tex.z-dn.net/?f=%5Cmathbb%20E%5BcY-d%5D%3Dc%5Cmathbb%20E%5BY%5D-d)
![\mathbb E[aX-b]\mathbb E[cY-d]=ac\mathbb E[X]\mathbb E[Y]-ad\mathbb E[X]-bc\mathbb E[Y]+bd](https://tex.z-dn.net/?f=%5Cmathbb%20E%5BaX-b%5D%5Cmathbb%20E%5BcY-d%5D%3Dac%5Cmathbb%20E%5BX%5D%5Cmathbb%20E%5BY%5D-ad%5Cmathbb%20E%5BX%5D-bc%5Cmathbb%20E%5BY%5D%2Bbd)
Putting everything together, we find the covariance reduces to
![\mathrm{Cov}(aX-b,cY-d)=ac(\mathbb E[XY]-\mathbb E[X]\mathbb E[Y])=ac\mathrm{Cov}(X,Y)](https://tex.z-dn.net/?f=%5Cmathrm%7BCov%7D%28aX-b%2CcY-d%29%3Dac%28%5Cmathbb%20E%5BXY%5D-%5Cmathbb%20E%5BX%5D%5Cmathbb%20E%5BY%5D%29%3Dac%5Cmathrm%7BCov%7D%28X%2CY%29)
as desired.
The smallest the absolute value will ever be is zero so the left side won't ever be smaller than -2 so won't ever be less than -3.
D. No solution
Answer:
If two figures are similar, then the correspondent sides are related by a constant factor.
For example, if the base of one side of one of the figures has a length L, then the correspondent side of the other figure has a length k*L where k is the scale factor.
Let's start with the two left triangles.
In the smaller one the base is 5, and the base of the other triangle is 15.
Then we will have:
15 = k*5
15/5 = k = 3
The scale factor is 3.
Then we will have that:
a = scale factor times the correspondent side in the smaller triangle:
a = k*3 = 3*3 = 9
a = 9
For the other two triangles, the base of the smaller triangle is 12, while the base of the larger triangle is 20.
Then we will have the relation:
12*k = 20
k = (20/12) = 10/6 = 5/3
The scale factor is 5/3
This means that the unknown side b is given by:
b*(5/3) = 15
b = (3/5)*15 = 3*3 = 9
b = 9.
