An inverse variation will have y increase while x decreases and vice versa. The graph is a hyperbola centred at the origin.
The equation is
y=k/x where k>0.
A direct variation will have x and y proportionately increase or decrease. The graph is a straight line through the origin. The equation is
y=kx where k>0.
In the examples below, the red curve is a direct variation, and the blue curve is an inverse variation, both with constant k=2.
