Straight Lines

A line parallel to x

A line parallel to x-axis has equation y = b (constant y-coordinate), while a line parallel to y-axis has equation x = c (constant x-coordinate). Thes

This form directly shows the slope

This form directly shows the slope (m) and y-intercept (c) of a line. The slope represents the rate of change of y with respect to x. Example: For lin

Used when a point (x₁

Used when a point (x₁, y₁) on the line and the slope m are known. This form is derived from the definition of slope. Example: Find equation of line th

When two points (x₁

When two points (x₁, y₁) and (x₂, y₂) are given, the equation is: (y - y₁)/(y₂ - y₁) = (x - x₁)/(x₂ - x₁). This is derived by first finding slope, the

Where a is x

Where a is x-intercept and b is y-intercept. This form is useful when intercepts are known or need to be found quickly. Example: Line with x-intercept