3x -4y = 12
3x -12 = 4y
Divide by 4
3/4x -3 = y
This is the point -slope form of a linear equation,
y = 3/4x -3
The slope is positive rising from quadrant 3, briefly through quadrant 4 and up into quadrant 1, intersecting -3 on the y axis and 4 on the x axis.