Algebra/Slope

Slope is the measure of how much a line moves up or down related to how much it moves left to right.

In this image, the slope of the blue line is a / 1 or (x₂ - x₁) / y₂ - y₁.

The green line is perpendicular to the blue one, meaning it forms a right angle with it, and its slope is - 1 / (slope of blue line).

Parallel lines are those that have the same slope and do not touch. Examples include latitude lines.

Slope-Intercept Form

The slope-intercept form of an equation, or $y=mx+b$, makes it easy to graph an equation and find its slope and y-intercept.

m = slope

y-intercept = (0, b)

To graph an equation from slope-intercept form, first put a dot on (0, b), then go right 1 unit, and up or down m units. Connect the dots and extend.

Point-Slope Form

y = m(x - x₁) + y₁
y - y₁ = m(x - x₁), where (x₁, y₁) is a point on the line.
This form can easily be converted to slope-intercept form once the point is found. Template:Subject