In the equation of a line represented as y = mx + b, the letter b stands for the y-intercept of the line. This is the point at which the line crosses the y-axis on a graph.
To explain further, when you set x = 0 in the equation, you solve for y, which gives you y = b. Thus, b tells us the value of y when the line intersects the y-axis. For example, if b = 3, the line will cross the y-axis at the point (0, 3).
Understanding the role of b helps in visualizing how the line is positioned on the coordinate plane and how it relates to changes in the slope, represented by m.