A graph has seconds after water began leaking on the x-axis, and volume of water in cup (milliliters) on the y-axis. A line goes through points (4, 8) and (6, 1). The graph shows the volume (y) of a cup of water (in ml). The cup has a small leak and the volume of water is decreasing at a constant rate each second (x). The situation can be expressed as a linear equation. Which values are correct for the slope and the y-intercept of the graph?
m = –1.5, b = 22
m = –3.5, b = 22
m = –3.5, b = 420
m = –1.5, b = 420