check the slope between the moving points
slope between (–6, –1) & (–3, 2) = 1
slope between (-3, 2) & (–1, 4) = 1
slope between (-1, 4) & (2, 7) = 1
the points are collinear and make an angle of 45 degrees with the x-axis
we can have an equation of a line passing through (-6,-1) and slope 1 as
(y + 1) = 1(x + 6)
y = x + 5 is your linear model mostly