Algebra 1 · Functions

Graph absolute-value functions

Graph absolute-value functions.

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What you’ll learn

Graph absolute-value functions.

Key idea

The inner zero locates the vertex horizontally; signed outer coefficient determines opening and arm steepness.

Vertex input and height differ; each ray must have the same signed distance coefficient.

Worked example

Enter the exact value or ordered values in the format requested below.

Full V graph consists of straight rays from V through all L/R marks; x horizontal, y vertical. Read the numerical x-coordinate of the vertex.

-6-4-202466420-2-4-6VLRLRxy

Marked coordinates: V=(-3, 4); L=(-4, 1); R=(-2, 1); L=(-5, -2); R=(-1, -2).

  1. The two straight rays meet at V=(-3,4); output changes -3 per unit distance from the vertex.
  2. Equation y=-3|x+3|+4 gives the same vertex, direction and linear offset heights; construction V:(-3,4);L:(-4,1);R:(-2,1).

Answer: -3

Quick Check

Relate the graph used in 'Graph absolute-value functions' to an equation, table, transformation, or verbal description.

Full V graph consists of straight rays from V through all L/R marks; x horizontal, y vertical. Connect to an equation using the vertex and signed arm slopes.

-6-4-202466420-2-4-6-8-10VLRLRxy

Marked coordinates: V=(2, -4); L=(1, -7); R=(3, -7); L=(0, -10); R=(4, -10).

Choose one answer

Show a hint

Locate the common meeting point of the two straight rays.