Answer:
y=1
Step-by-step explanation:
6=2(y+2)
6=2y+4
2=2y
y=1
Answer: Is true sometimes.
Step-by-step explanation:
I guess that here we have two matrices, A and B, that are nxn.
We can see that if those matrices can conmutate, then we can try it with some simple matrices.
![A = \left[\begin{array}{ccc}1&0\\0&-1\end{array}\right] . B = \left[\begin{array}{ccc}2&0\\1&1\end{array}\right]](https://tex.z-dn.net/?f=A%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%260%5C%5C0%26-1%5Cend%7Barray%7D%5Cright%5D%20.%20B%20%3D%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%260%5C%5C1%261%5Cend%7Barray%7D%5Cright%5D)
Here, we would have that:
![AB = \left[\begin{array}{ccc}2&0\\-1&-1\end{array}\right]](https://tex.z-dn.net/?f=AB%20%3D%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%260%5C%5C-1%26-1%5Cend%7Barray%7D%5Cright%5D)
![BA = \left[\begin{array}{ccc}2&0\\1&-1\end{array}\right]](https://tex.z-dn.net/?f=BA%20%3D%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D2%260%5C%5C1%26-1%5Cend%7Barray%7D%5Cright%5D)
You can see that AB and BA are different, then the statement is not always true.
But it is true sometimes, if A or B are the identiti, then I*A = A*I, in this case would be true.
It is also true if A and B are diagonal matrices, let's prove it:
![A = \left[\begin{array}{ccc}a&0\\0&b\end{array}\right] , B = \left[\begin{array}{ccc}c&0\\0&d\end{array}\right]](https://tex.z-dn.net/?f=A%20%3D%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Da%260%5C%5C0%26b%5Cend%7Barray%7D%5Cright%5D%20%2C%20B%20%3D%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dc%260%5C%5C0%26d%5Cend%7Barray%7D%5Cright%5D)
![AB = \left[\begin{array}{ccc}ac&0\\0&bd\end{array}\right] = BA](https://tex.z-dn.net/?f=AB%20%3D%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dac%260%5C%5C0%26bd%5Cend%7Barray%7D%5Cright%5D%20%3D%20BA)
-8 - 5n = 64 + 3n
+5n +5n add 5n to both sides, 5n's cancel out on the left.
______________
-8 = 64 + 8n
-64 -64 subtract 64 on both sides, 64's cancel out on the right.
______________
-72 = 8n
___ ___ divide 8 on both sides, 8's cancel out from the right.
8 8
n= -9, final answer
Answer:
14130 ft^3
Step-by-step explanation:
The formula for the volume of a cone of radius r and height h is
V = (1/3)*pi*r^2*h.
Here, V = (1/3)(3.14)(15 ft)^2*(60 ft) = 20*3.14*225 ft^3 = 14130 ft^3
Answer:
B and D
Step-by-step explanation:
Distributive property on 3(c-3) is 3c-12=20. D is the same. Divide instead.