An object moves at a constant rate. The graph shows the object's height at different times. Which equation represents the situation?
Ay = −15x 900
By = −15x − 900
Cy = 15x − 900
Dy = 15x 900
Ay = −15x 900
By = −15x − 900
Cy = 15x − 900
Dy = 15x 900