Y-intercept

Definition

The y-intercept is the point where a line or curve intersects the y-axis on a coordinate plane. It represents the value of the function at the point where the input (x-value) is zero, providing important information about the behavior and characteristics of the function.

5 Must Know Facts For Your Next Test

1. The y-intercept is a crucial parameter in the equation of a line, as it determines the starting point of the line on the y-axis.
2. In the slope-intercept form of a linear equation, $y = mx + b$, the y-intercept is represented by the constant term $b$.
3. The y-intercept can be used to determine the initial or baseline value of a function, which is important for understanding the behavior of the function.
4. Graphing linear equations by finding the x-intercept and y-intercept is a common technique used to visualize the relationship between variables.
5. The y-intercept, along with the slope, can be used to find the equation of a line given two points or one point and the slope.

Review Questions

• Explain how the y-intercept is used in the slope-intercept form of a linear equation.
  • In the slope-intercept form of a linear equation, $y = mx + b$, the y-intercept is represented by the constant term $b$. This value determines the starting point of the line on the y-axis, independent of the slope $m$. The y-intercept provides information about the initial or baseline value of the function, which is crucial for understanding the behavior and characteristics of the line.
• Describe the role of the y-intercept in the process of graphing linear equations.
  • When graphing linear equations, the y-intercept is one of the key pieces of information used to determine the position and orientation of the line on the coordinate plane. By finding the y-intercept, which represents the point where the line crosses the y-axis, you can plot the initial point of the line. This, combined with the slope of the line, allows you to construct the complete graph and visualize the relationship between the variables.
• Analyze how the y-intercept can be used to find the equation of a line given specific information.
  • The y-intercept, along with the slope of a line, can be used to determine the equation of a line in slope-intercept form, $y = mx + b$. If you know the coordinates of a point on the line and the slope, you can use this information to solve for the y-intercept $b$. Alternatively, if you know the coordinates of two points on the line, you can use them to calculate both the slope and the y-intercept, which fully defines the equation of the line.

Related terms

Slope-Intercept Form: The equation of a line in the form $y = mx + b$, where $m$ is the slope and $b$ is the y-intercept.

Intercepts: The points where a line or curve intersects the x-axis (x-intercept) or y-axis (y-intercept) on a coordinate plane.

Linear Equation: An equation that represents a straight line in a coordinate plane, with the general form $ax + by = c$.