Hey there!!!
What is slope-intercept form ?
The slope intercept form is y = mx + b
Where 'm' is the slope and 'b' is the y-intercept.
Given equation :
... 4x - 4y = 15
This is given is standard form.
Let's convert this into slope-intercept form.
... 4x - 4y = 15
... -4y = -4x + 15
... y = x + ( 15 / 4 )
Hence, the slope is '1'.
Hope my answer helps!