Helen has been working on a science project about plant growth. plant a started at a height of 6 cm and exhibited steady growth during the first four weeks of the project. after those four weeks, plant a was 26.8 cm in height.

in a linear model of plant a's growth, x represents the number of weeks after being planted, and y represents the plant's height in centimeters.

relative to this model, which of the following statements applies?