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Quadratic Relationships

Build confidence with parabolas, factoring, graph features, and real-world quadratic models.

What you will practice

  • Recognize quadratic relationships from x² terms, tables with constant second differences, graphs, and contexts.
  • Use standard form, factored form, and vertex form to identify the most useful graph features.
  • Factor simple quadratics and interpret zeros as solutions or x-intercepts.
  • Identify vertex, axis of symmetry, intercepts, maximums, and minimums.
  • Compare quadratic tables, equations, and real-world models with linear and exponential patterns.

Why it matters

Quadratics connect algebra to visible graph features. Students become stronger when they can choose the form that reveals what the question asks for: zeros, vertex, intercepts, maximums, or minimums.

Student-friendly anchor

Use the form that gives you the feature. y = ax^2 + bx + c shows the y-intercept, y = a(x - r)(x - s) shows zeros, and y = a(x - h)^2 + k shows the vertex.

What NC Math 1 expects

Based on the Math 1 standards for quadratic expressions, equations, functions, and model interpretation.

NC.M1.A-SSE.3

Choose and produce equivalent forms of quadratic expressions to reveal useful features.

NC.M1.A-APR.3

Use zeros and factors to connect algebraic expressions with graph behavior.

NC.M1.A-REI.4

Solve quadratic equations using structure, including factoring and square-root reasoning.

NC.M1.F-IF.7

Graph quadratic functions and identify key features from the graph or equation.

NC.M1.F-IF.8a

Use equivalent forms to reveal zeros, extreme values, and symmetry.

Words and ideas to know

These terms support table, graph, equation, and context questions.

Quadratic Function

A function whose highest power of x is x^2. Its graph is a parabola.

Parabola

The U-shaped graph of a quadratic function. It can open upward or downward.

Vertex

The turning point of a parabola. It gives the maximum or minimum value.

Axis of Symmetry

The vertical line through the vertex that splits the parabola into matching halves.

X-Intercepts

Points where the graph crosses the x-axis. They happen when y = 0.

Zeros

The x-values that make the function equal 0. Zeros match the x-intercepts.

Standard Form

A quadratic written as y = ax^2 + bx + c.

Factored Form

A quadratic written as y = a(x - r)(x - s), which helps reveal zeros.

Vertex Form

A quadratic written as y = a(x - h)^2 + k, which helps reveal the vertex (h, k).

Second Differences

The differences of the first differences in a table. Constant second differences suggest a quadratic.

Maximum

The greatest output value of a downward-opening parabola.

Minimum

The least output value of an upward-opening parabola.

How to think through quadratic questions

Keep the target feature in mind before you start calculating.

Check tables

Equal first differences mean linear. Equal second differences mean quadratic.

Use factored form

In y = (x - 2)(x + 5), the zeros are x = 2 and x = -5.

Use vertex form

In y = a(x - h)^2 + k, the vertex is (h, k).

Interpret context

Zeros can mean when something starts or lands. The vertex can mean the greatest height, greatest profit, or least cost.

Choose a Quadratic Relationships set

Start with DOK 1 fluency, then build toward applications, analysis, and EOC-style mixed practice.