CurriculumGrade 9Mathematics

Graphing Key Features

Aligned to F-IF.C.7 — Common Core State Standards for Mathematics.

What this lesson teaches

To graph a function, plot its key features: intercepts (where it crosses the axes), and for a quadratic, its vertex. Then connect the points smoothly following the function's shape.

Worked example

Graph y = x^2 − 4. The y-intercept is (0, −4). Setting y = 0 gives x^2 = 4, so x = 2 or x = −2 — the x-intercepts are (2, 0) and (−2, 0), and the vertex is (0, −4).

Practice questions

  1. Find the x- and y-intercepts of y = 2x − 6.
  2. Find the vertex and y-intercept of y = x^2 − 9.
  3. Where does the graph of y = x^2 touch the x-axis?

Watch the lesson

Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.

▶ Watch this lesson

En español

Graficar Características Clave

Para graficar una función, marca sus características clave: las intersecciones (donde corta los ejes) y, para una cuadrática, su vértice. Luego une los puntos suavemente siguiendo la forma de la función.

Ejemplo: Grafica y = x^2 − 4. La intersección con el eje y es (0, −4). Al hacer y = 0 queda x^2 = 4, así que x = 2 o x = −2: las intersecciones con el eje x son (2, 0) y (−2, 0), y el vértice es (0, −4).

More Functions lessons

Interpreting Graphs of FunctionsF-IF.B.4What Is a Function?F-IF.A.1Evaluating FunctionsF-IF.A.2Sequences as FunctionsF-IF.A.3Domain in ContextF-IF.B.5Average Rate of ChangeF-IF.B.6

Teach this lesson today

An AI tutor that guides with questions instead of just giving answers — all K–12 core subjects, every child in the family.

Start free — no card required