Equation of a Straight Line
This page introduces the fundamental concepts of linear equations and provides methods for finding the equation of a line given two points. The content focuses on the slope-intercept form of a line equation, y = mx + c, where m represents the gradient and c is the y-intercept.
Definition: The equation of a straight line in slope-intercept form is y = mx + c, where m is the gradient slope and c is the y-intercept.
The page demonstrates how to calculate the gradient using the formula for gradient of a line with two points: m = y2−y1 / x2−x1. This formula is essential for determining the slope of a line when given two points on that line.
Example: To find the equation of a line passing through 4,1 with a gradient of 3, the process involves using the point-slope form: y - y₁ = mx−x1. Substituting the values gives y - 1 = 3x−4, which simplifies to y = 3x - 11.
The document also covers how to find the equation of a line given two points, such as A−2,0 and B1,6. It walks through the process of calculating the gradient and determining the y-intercept to form the complete equation.
Highlight: Understanding how to derive the equation of a line from two points is crucial for graphing linear functions and solving real-world problems involving linear relationships.
Vocabulary: The y-intercept is the point where a line crosses the y-axis, typically represented as 0,c in the coordinate plane.