Answer:
Problem 1: 
Problem 2: 
Problem 3: 
Step-by-step explanation:
Problem 1:
So we are going to use the following to help us:
So if we make those substitution into the first equation we get:
Factor the 
out:
The following is a Pythagorean Identity: 
.
We will apply this identity now:
This implies:
We don't need both because both of include points with radius 4.
Problem 2:
Factoring out from first two terms:
Apply the Pythagorean Identity I mentioned above from problem 1:
or if we factor out r:
r=0 is actually included in the other equation since when theta=0, r=0.
Problem 3:
Answer:
B.
Step-by-step explanation:
The function is positive when it is above the x-axis
The following x values are where the function has positive y coordinates:
(-2,0)
(4,inf)
The function is negative when it is below the x-axis
The following x values are where the function has negative y coordinates:
(-inf,-2)
(0,4)
So you should see all of these intervals listed in choice B
X=10 y=-1
U can use Photomath for questions like this
Her final payment is 78$. Just do 50+52+54+56+58... and so on until you get up into the 1,100's. Then subtract that last number you got from 1200. The answer is 78.
