#### Answer

(a) The point $(4,-3)$ lies on the graph.
(b) The point $(8,1)$ does not lie on the graph.

#### Work Step by Step

(a) We can verify if the point $(4,-3)$ satisfies the equation of the graph:
$5x-4y = 5(4)-4(-3) = 20+12 = 32$
The point $(4,-3)$ lies on the graph.
(b) We can verify if the point $(8,1)$ satisfies the equation of the graph:
$5x-4y = 5(8)-4(1) = 40-4 = 36$
The point $(8,1)$ does not lie on the graph.