Option D:
is the domain of the function.
Solution:
Given function is

<u>To find the domain of the function:</u>
Option A: 
Substitute x = 0 in r(x).

If x = 0, then r(0) = 0
So that x ≠ 0 is false.
So,
is not the domain of the function.
Option B: 
Substitute x = –1 in r(x).

If x = –1, then r(–1) = 1
So that x = ± 1 is false.
So,
is not the domain of the function.
Option C: 
Substitute x = 1 in r(x).

It is indeterminate.
So, all real numbers are not the domain of the function.
Option D: 
Substitute x = 1 in r(x).

It is indeterminate.
So,
is the domain of the function.
Together it would take a total of 4 hours to completely fill the pool.
1760 divided by 4 equals 440. This is the amount of liters that the second pump will fill the pool in 4 hours, so 440 divided by four is the amount that the second pump will fill the pool in one hour. 440/4= 110.
Now we add 110 to 330 to get the hourly rate of both pumps filling the pool. 110+330=440.
1760/440 equals 4.
So it takes 4 hours for both pumps to fill the pool.
Hope this helps!
I think it is B
Hope my answer help you?
Answer:
A
Step-by-step explanation:
This is from the definition of an inverse matrix. Always will be 1 when multiplied.
Given :
Emily sells erasers for $2 per package and pencils for $5 per package. she sells 220 total packages and earns $695.
To Find :
The number of packages of erasers and pencils that were sold
.
Solution :
Let, number of erasers are x and pencils are y.
So, x + y = 220 ....1
Also, 2x + 5y = 695 ....2
Solving equation 1 and 2, we get :

x = 220 - 85 = 135
Therefore, the number of packages of erasers and pencils that were sold are 135 and 85 respectively.
Hence, this is the required solution.