Direct and inverse variation depend on the relationships between two variables, such as x and y.

Explain how the constant k is represented in inverse variations.

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.