Write the Equation
Part of the Graphs & Systems section of Coddy's Algebra journey. Lesson 19 of 64.
To write a line's equation in slope-intercept form, substitute its slope for m and its y-intercept for b in y = mx + b. A line with slope -2 passing through (0, 5) has the following equation.
y = -2x + 5
Here, m = -2 and b = 5. If the same slope is paired with the intercept (0, -3), then b = -3, giving y = -2x - 3.
A nonvertical line can be represented by a graph, a table of points, a description, or an equation. Use its slope and one point to write its equation.
Challenge
MediumA line has slope -3 and y-intercept (0, 4). Write its equation.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Graphs & Systems
1The Coordinate Plane
Two Numbers, One PointThe Four QuadrantsPoints on the AxesMirror PointsRecap: The Plane4Slope-Intercept Form
y = mx + bThe Starting HeightWrite the EquationSolve for yDraw From Any FormRecap: y = mx + b7Parallel & Perpendicular
Same Slope, Never MeetThe Perpendicular SlopeA Right-Angle LineRecap: Two Relations2From Rule to Line
A Rule Makes PointsThe Points Line UpOn the Line or Not?Between the DotsRecap: Rule to Line