Answer:
Given speed of trolley = 125 meters per minute

Now we know that
Distance= Speed x time
Thus for the first case since the time of travel is less than 450 seconds thus the distance traveled is less than
Distance < 2.083 x 450 =937.5 meters
hence depending on the given information we cannot come to any conclusion weather the distance travelled is less than 800 m or greater than 800 m.
For the second case
since the time of travel is greater than 400 seconds
Thus the distance traveled is

which is greater than 800 meters.
It's going to be kind of crazy, but you need to use Pythagorean's Theorem for this. That will look like this:

. FOIL out the left side to get

. FOIL out the first of the 2 expressions on the right to get

, and the second of the 2 to get 4x. Our equation now looks like this:

. Combine like terms to get an equation that still has square roots in it that we have to deal with:

and

. We will square both sides to get rid of the square root sign.

. This is a polynomial now that can be factored to solve for x. Bring the 2x over by subtraction and set the polynomial equal to 0.

. Factor out an x, leaving us with x(x-2)=0. That means that x = 0 or x - 2 = 0 and x = 2. Of course if we are solving for the length of a side we know it can't have a side length of 0, so it must have a side length that is a multiple of 2. x = 2
-1 - (-7) = 6
5 - (-1) = 6
11 - 5 = 6
The common difference is 6.
If you add 6 to a term, you get the next term.

As a function this is x=3 y=3