We've updated our
Privacy Policy effective December 15. Please read our updated Privacy Policy and tap


Study Guides > College Algebra CoRequisite Course

Summary: Equations of Lines

Key Concepts

  • Given two points, we can find the slope of a line using the slope formula.
  • We can identify the slope and y-intercept of an equation in slope-intercept form.
  • We can find the equation of a line given the slope and a point.
  • We can also find the equation of a line given two points. Find the slope and use point-slope form.
  • The standard form of a line has no fractions.
  • Horizontal lines have a slope of zero and are defined as [latex]y=c[/latex], where c is a constant.
  • Vertical lines have an undefined slope (zero in the denominator) and are defined as [latex]x=c[/latex], where c is a constant.
  • Parallel lines have the same slope and different y-intercepts.
  • Perpendicular lines have slopes that are negative reciprocals of each other unless one is horizontal and the other is vertical.


the change in y-values over the change in x-values

Licenses & Attributions

CC licensed content, Original

CC licensed content, Shared previously

  • College Algebra. Provided by: OpenStax Authored by: Abramson, Jay et al.. Located at: https://openstax.org/books/college-algebra/pages/1-introduction-to-prerequisites. License: CC BY: Attribution. License terms: Download for free at http://cnx.org/contents/[email protected].