Step-by-step explanation:
you drew already the right things, you have everything.
so, what is the problem ?
the most common form of line equation is
y = ax + b
a is the slope of the line. it is expressed as the ratio
y coordinate change / x coordinate change
when going from one point to the other.
b is the y-intercept (the y value when x = 0).
once we have the slope, we get b by using the coordinates of one of the given points as x and y in the equation and solve for b.
so, for the 2 marked points you showed correctly the differences :
x changes by +8 (from -4 to 4).
y changes by -2 (from 3 to 1).
so the slope is -2/+8 = -1/4
the y-intercept we also see directly in the chart : +2.