Step-by-step explanation:
let's develop the slope intercept form for this line.
in general that is
y = ax + b
a is the slope, and b is the y-intercept (the y value when x = 0, because that is where the line intercepts the y-axis).
let's start with the first point or x, y pair : (-72, 25)
25 = a×-72 + b = -72a + b
b = 72a + 25
and with the second point or x, y pair : (-54, 13)
13 = a×-54 + b
b = 54a + 13
so, when combining both equations (as b = b, of course)
72a + 25 = 54a + 13
18a = -12
a = -12/18 = -2/3
b = 54a + 13 = 54×-2/3 + 13 = -36 + 13 = -23
so, the y-intercept point is (0, -23).
