Question

Which graph of ordered pairs shows a proportional relationship?
On a coordinate plane, points (1, negative 2) and (2, negative 4) are plotted.
On a coordinate plane, points (negative 2, negative 2) and (1, 3) are plotted.
On a coordinate plane, points (negative 2, 1) and (1, negative 2) are plotted.

Answer 1

The first one: (1, −2) and (2, −4).

Reason: y/x = −2/1 = −4/2 = −2, so y = −2x (a constant of proportionality) and the line through those points passes through the origin. The other pairs do not.