Which graph descriptions represent direct proportion? Select all that apply.
The graph is the line y = 2x.✓Bonne réponse
The graph is a straight line through points (0, 0) and (3, 12).✓Bonne réponse
The graph is straight through the origin with constant nonzero y/x.✓Bonne réponse
The graph is the horizontal line y = 5.
Explication
The line y equals 2 times x, the line through the listed origin and point, and any straight line with a constant nonzero y divided by x all meet the origin and constant-ratio conditions. A horizontal line at y equal to 5 is the closest distractor because it is straight, but its nonzero intercept prevents direct proportion.