Answer: 
Step-by-step explanation:
1. To find the equation asked, you must add the times:

Where
is the time takes Lilly in her path to work and
is the time takes Lilly in her path to home.
2. You must use the following formula of speed and solve for the time

Where n is the distance, V is the speed and t is the time.
3. You know that Lilly takes a train each day to work that averages 35 miles per hour, then, you can write the following expression:

4. And her train ride follows the same path at 45 miles per hour:

5. Then, you obtain the following equation:

Answer:
population = 5652 people
Step-by-step explanation:
area = πr² = (3.14)(6²) = 113.04 mi²
at 50 people/mi², then 113.04 x 50 = 5652 people
Are you trying to find a?
For part A Amy's estimate is inaccurate because when adding fractions they must have the same denominators. Amy probably made the mistake of adding 1/4 and 1/3 without changing the denominators first which gave her 1/7. If she were to do it correctly then she would've ended up with 7/12 as her answer.
My work:
1/4=3/12
1/3=4/12
4/12+3/12=7/12
I hope this helps and if I gave any false information I apologize in advance.
You can describe the domain by every possible x value in the function, since that function has a vertical intersection line which means the x value will never pass it on the negative side, the domain would be from -2 to all the postive numbers, X > -2 or (-2,∞).
For the range, simply it's all the possible y values. In that function it's impossible to go under 0 or negative value. That means the range would be Y>0 or (0,∞).
If you want to know if it's a function or not you could try the vertical line test, select any x value and draw straight line on it, if the line crosses 2 y points in the same x value it wont be a function, In your case each x value has it's own Y value.
So the answer is Domain x>-2; Range y>0; Yes, it is a function