Step-by-step explanation:
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. or we get the point of the line directly on the y-axis.
we see several marked points.
e.g.
(-4, 4) (0, -4)
x changes by +4 (from -4 to 0)
y changes by -8 (from 4 to -4)
the slope (a) is -8/+4 = -2
the y-intercept is given by the point (0, -4), because this is where x=0.
so, it is -4
and the line equation is
y = -2x - 4
