First of all you need to rearrange the equation to slope-intercept form which is y = mx+b.
so; 4x - 3y = 12.3 will be
-3y = 12.3 - 4x
rearrange so it will be easy to isolate your y.
-3y = -4x + 12.3
divide both sides by -3
-3y/-3 = -4x/-3 + 12.3/-3
y = 4x/3 - 4.1
so: slope 'm' = 4x/3
y-intercept = -4.1
x-intercept = 0