Can you pls i don't understand pls

We are given the following data in tabulated form:

time (minute), x                               distance from surface (m), y

0                                                              63          

1                                                              105

2                                                              147

3                                                              189

We can see that for every 1 minute increase in time, there is a constant 42 m increase in distance from the surface. Therefore the equation relating the two variables is linear in the form:

y = m x + b

where m is the slope and b is the y-intercept

Part A.

We can use the similar triangles to explain why the slope at points A and B is similar as the slope at points A and C by calculating for the slope in each case. The formula for slope m is:

m = (y2 – y1) / (x2 – x1)

Slope between A (2, 147) and B (1, 105):

mAB = (147 - 105) / (2 – 1) = 42

Slope between A (2, 147) and C (0, 63):

mAC = (147 - 63) / (2 – 0) = 42

Hence mAB = mAC

Part B.

The intial value is the value of y intercept (b). The value of b is the value of y when x = 0, hence:

initial value = b = 63

The slope of the graph is m = 42 and it tells us that there is 42 m change in distance per 1 minute of time.