Slope-intercept form:
y = mx + b
where m is the slope and b is the y-intercept
4y - 8x = 9
4y = 8x + 9
dividing the whole equation with 4 you'll have:
y = 2x + 9/4
comparing the resulting equation to the slope-intercept form we may have m=2,b=9/4
therefore the slope of the line is 2
