What Is a Function? (One Input, Exactly One Output!) | 8th Grade Math (Video 20)

Press B3, get the chips — every single time. That's a function. Press B3 and get chips-or-maybe-a-granola-bar? Broken machine. 🕵️ The Functions unit opens with the one law that decides everything: every input gets exactly ONE output. In this video you will: ✓ State the definition of a function and its one unbreakable clause ✓ Interrogate ordered pairs, mapping diagrams, and tables for split inputs ✓ Use the VERTICAL LINE TEST to judge any graph instantly ✓ Learn why repeated outputs are innocent — and repeated inputs are conditional ✓ Evaluate f(x) like a name tag, and keep domain and range straight TIMESTAMPS 00:00 What Is a Function? 00:40 The law: one input, exactly one output 01:25 Read every costume: pairs, mappings, tables 02:06 The vertical line test 02:47 The innocence clause: repeated outputs 03:30 The name tag f(x), domain, and range 04:13 Example 1: input 2 splits — not a function 04:51 Example 2: the well-behaved file — function 05:38 Example 3: the table twins 06:20 Example 4: name tag at work — f(3), f(0), f(-2) 07:04 Example 5: circle vs parabola face the line 07:46 The Function Rulebook 08:45 Practice 1: the repeat parade 09:12 Practice 1: the reveal — function! 09:48 Practice 2: the sideways suspect 10:15 Practice 2: the reveal — not a function 10:53 Practice 3: name-tag arithmetic 11:21 Practice 3: the reveal — g(2) = 3, g(-3) = 8 11:56 Recap: the law stands 12:50 Next: Comparing Functions Common Core: 8.F.A.1 — Understand that a function is a rule that assigns to each input exactly one output. Five case files, three practice verdicts, and one very suspicious circle. Pause, judge, THEN watch the reveal! #8thGradeMath #Functions #VerticalLineTest #Algebra #MathHelp #MiddleSchoolMath #CommonCore #SchoolMadeClear