Given a graph with points A and B, determine the coordinates of A and B, the gradient of line AB, and the equation of line AB in the form y = mx + c.

Point A is located at $x=4$ and $y=3$.
Coordinates of A: $\boxed{(4, 3)}$

Point B is located at $x=6$ and $y=-5$.
Coordinates of B: $\boxed{(6, -5)}$

Let $A = (x_1, y_1) = (4, 3)$
Let $B = (x_2, y_2) = (6, -5)$

The gradient $m$ is given by the formula:

The gradient of line AB is $\boxed{-4}$.

The equation of a line can be written in the point-slope form: $y - y_1 = m(x - x_1)$.

The equation of line AB is $\boxed{y = -4x + 19}$.