What is the y-intercept of a line?

What is the y-intercept of a line?

• A. The distance between intercepts
• B. The y-intercept is the point where the line crosses the y-axis
• C. The slope of the line
• D. The point where the line crosses the x-axis

Answer: (B)

The main idea is where a line meets the vertical axis. The y-intercept is the point where the line crosses the y-axis, which means the x-coordinate is zero at that point. In slope-intercept form, y = mx + b, the constant b is exactly the y-coordinate when x is zero, so that point is the y-intercept. For example, if the line passes through (0, 4), the y-intercept is 4. It’s not the distance between intercepts, not the slope, and not the point where the line crosses the x-axis (that would be the x-intercept, where y = 0).

The main idea is where a line meets the vertical axis. The y-intercept is the point where the line crosses the y-axis, which means the x-coordinate is zero at that point. In slope-intercept form, y = mx + b, the constant b is exactly the y-coordinate when x is zero, so that point is the y-intercept. For example, if the line passes through (0, 4), the y-intercept is 4. It’s not the distance between intercepts, not the slope, and not the point where the line crosses the x-axis (that would be the x-intercept, where y = 0).