Find the slope: 4x-5y = 20

Answer 1

rearrange as
5y = 4x-20
now divide by 5
y = 4/5 x - 4
recall the slope-intercept form for a line: y = mx+b
where m is the slope.
So, your slope is m = 4/5

Answer 2

Also, slope = -A/B = -4/-5 = 4/5.