When (1,2) is substituted into the first equation, the equation is true.
The ordered pair (1,2) is a solution to the system of linear equations.
When (1,2) is substituted into the second equation, the equation is true.
Both trains travel for 7 time units.
Train A travels 385 distance units, so its speed is

Train B travels 577.5 distance units, so its speed is

Note that the units are not specified, but considering that we're talking about trains, the graph is likely to be showing distance in km (or miles) and time in hours.
Also, the distance traveled by train B is not perfectly aligned with the grid, so I assumed that it was the average between the two ticks of 550 and 605.
Step-by-step explanation:
count the slope, 5 up in 2.5 horizontal steps, slope = 5/2.5 or 2
x intercept is on the graph, 2.5
y intercept is also on the graph, -5
Short answer: Yes.
Each member of the sequence is multiplied by 5 to get to the next member of the sequence.
Find the general equation.
tn = a*5^(n - 1)
Example
t4 = 1*5^(4 - 1)
t4 = 1*5^3
t4 = 125 just as the sequence shows.
t5 = 1^5^4
t5 = 625 Any member of the sequence can be found this way.