If we have a y intercept of -8, that means that the point falls on the y-axis, therefore x = 0. So, we have a point (0, -8) and we have a slope m = 23.
y = mx + b
y = 23x + b
Now, we can plug in the point values x = 0, y = -8
-8 = 0 + b
b = -8
If we plug b back into our original formula, we get:
y = 23x - 8