In this question all required information's are already provided. Based on these details the answer to the question can be easily determined. Let us now write down all the information's that are already given.
Mass of the roller coaster = 1000 kg
Velocity of the roller coaster = 20.0 m/s
We know the formula for finding the kinetic energy is
Kinetic energy = 0.5 * mass * (velocity) ^2
= 0.5 * 1000 * (20)^2
= 0.5 * 1000 * 400
= 200000 Joules
So the Kinetic energy of the roller coaster is 200000 joules.
X= 2.5 that is the correct answer
Next term = 10
You add 3 to each term to get the next
1+3 = 4
4+3 = 7
7+3 = 10
etc etc
The domain of the sequence is 1,2,3,4,... basically the set of positive whole numbers. This is known as the set of natural numbers or counting numbers. We don't include 0. The domain is the set of possible inputs for 'n' in the formula mentioned below.
The range is the sequence of values shown.
The formula to generate the sequence is
an = 3n-2
as shown by these steps below
an = a1 + d(n-1)
an = 1 + 3(n-1)
an = 1+3n-3
an = 3n-2
To get any term you want, plug in a whole number for n. For example, plug in n = 4 to get...
an = 3n-2
a4 = 3*4-2
a4 = 12-2
a4 = 10
Showing that the fourth term is 10 as found earlier above.
So, we will be using point-slope form to construct this equation.
Point-slope form's general formula is as follows:

M is the slope,
Y₁ is the Y-coordinate of the point
X₁ is the X- coordinate of the point.
So, our slope is 3 (since the equation is given in slope-intercept form)
Our Y₁ is 7 and out X₁ is 4
So, now we just plug our numbers into the equation.

There's your equation.
Hope this helps!