Straight Lines

The slope (m) of a line

The slope (m) of a line is defined as the tangent of its angle of inclination with the positive x-axis. For a line passing through points (x₁,y₁) and

Equation

Equation: y - y₀ = m(x - x₀), where (x₀,y₀) is a known point and m is the slope. Example: Line through (2,3) with slope 4 has equation y - 3 = 4(x - 2

Equation

Equation: (y - y₁)/(x - x₁) = (y₂ - y₁)/(x₂ - x₁). Example: Line through (1,2) and (4,8) gives (y-2)/(x-1) = (8-2)/(4-1) = 6/3 = 2, so y - 2 = 2(x - 1

Equation

Equation: y = mx + c, where m is slope and c is y-intercept. Example: y = 3x + 2 represents a line with slope 3 and y-intercept 2. The line crosses th

Equation

Equation: x/a + y/b = 1, where a is x-intercept and b is y-intercept. Example: x/3 + y/4 = 1 represents a line crossing x-axis at (3,0) and y-axis at