Lesson 5 of 10

📈 Functions and the Coordinate Plane

🎓 Grades 9–12 ⏱ ~35 minutes 🟡 Intermediate

What You'll Learn

  • What a function is: one input → exactly one output
  • Plot ordered pairs and read a coordinate graph
  • Identify functions from tables, mappings, and graphs (vertical line test)
Quick Check

1. Is {(1,2), (2,4), (1,5)} a function?

AYes
BNo — x=1 maps to two outputs
CYes, if we only count unique y-values

2. What is f(4) if f(x) = 3x − 5?

A7
B7
C17

2. What is f(4) if f(x) = 3x − 5?

A7
B−5
C17

3. The point (−2, 5) is in which quadrant?

AQuadrant I
BQuadrant II
CQuadrant III

4. Which describes the vertical line test?

AAll y-values must be positive
BEach vertical line crosses the graph at most once
CThe graph must be a straight line
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