Skill: Determine the y-intercept from an equation

Explanation and Free Practice Resources

The y-intercept is the y-coordinate of the point where a linear relation crosses the y-axis, found by setting x=0x=0 and solving for yy; in y=mx+by=mx+b, it is bb, and in other forms it may require rearranging the equation. This connects an equation to its graph and distinguishes the y-intercept from the x-intercept; nonlinear relations, vertical lines, and generalized parameter-based cases are not included.

Detailed Explanation: Determine the y-intercept from an equation

The y-intercept is where a line crosses the yy-axis. Every point on the yy-axis has an xx-coordinate of 00.

To find the y-intercept:

  1. Substitute x=0x=0 into the equation.
  2. Solve for yy.
  3. Write the intercept as the point (0,y)(0,y).

Example

Find the y-intercept of

2x+3y=122x+3y=12

Set x=0x=0:

2(0)+3y=122(0)+3y=12

Simplify:

3y=123y=12

Divide both sides by 33:

y=4y=4

Therefore, the y-intercept is

(0,4)\boxed{(0,4)}

The line crosses the yy-axis at (0,4)(0,4). The y-intercept is not found by setting y=0y=0; that would find the x-intercept instead.

Learn by doing: Determine the y-intercept from an equation

Click a topic below to practice the foundational skills you'll need, learn the steps, or master this skill

Your results

Practice with unlimited practice problems

Linear Equations - Find Y Intercept (Integer) - Standard Form


    ?

    Download/Modify Free Grade 9 'Determine the y-intercept from an equation' Worksheet

    Print this free 'Determine the y-intercept from an equation' worksheet to practice this skill away from the computer. Click 'Modify' to easily customize this worksheet to your exact needs.

    Units Teaching This Skill

    These adaptive units introduce, teach, or reinforce this skill (Determine the y-intercept from an equation) through scaffolded problems that grow in difficulty as concepts are understood.

    Explore More Grade 9 Math