8th Grade · Functions

Y-Intercept

8.EE.B.6 · 8.F.A.3 · 8.SP.A.3

Definition

The point where a function's graph crosses the y-axis, equal to the output when the input is zero. In a linear function it is the initial value b.

Examples

  • In f(x) = 2x + 1, the y-intercept is 1, since f(0) = 1.
  • The y-intercept is the starting amount before any change.

Key rule

Set x = 0 to find the y-intercept.

Memory hook

Where the line crosses the y-axis.