Step-by-step explanation:
that is also called the slope or inclination or change rate.
that is the ratio of y change / x change.
when going from point 1 to point 2 (the sequence is not important, but once you picked one you need to use it for x and y), we see
x changes by +2 (from 2 to 4).
y changes by +2 (from 4 to 6).
so it is +2/+2 = 2/2 = 1/1 = 1