Direct & Inverse Variation Unit Review

Direct variation is a relationship between two variables where one variable is a constant multiple of the other. It can be expressed as y = kx, where k is a non-zero constant.

Inverse variation is a relationship between two variables where the product of the two variables is a constant. It can be expressed as y = k/x, where k is a non-zero constant.

k = y/x = 3/12 = 1/4.

y = -20/4 = -5.

The graph of a direct variation is a straight line that passes through the origin (0,0).

The graph of an inverse variation is a hyperbola that approaches the axes but never touches them.

This is a direct variation.

k = yx = 10*2 = 20; y = 20/5 = 4.

In direct variation, as x increases, y also increases, and as x decreases, y also decreases.

In inverse variation, as x increases, y decreases, and as x decreases, y increases.