A relation is a function when every x goes to exactly one y. On a graph, that means no vertical line crosses it more than once. In a mapping diagram it means no input has two arrows leaving it; two inputs pointing at the same output is fine.
The vertical line x = 0 crosses it at y = 3 and at y = -3.
One x with two y-values.
The answer is Not a function.
Where students go wrong
Rejecting two inputs that share an output. That is still a function; only one input with two outputs breaks the rule, which is why a horizontal line passes and a vertical one does not.
Also called vertical line test, is it a function, function or not a function or mapping diagram.
What you can put on this worksheet
The vertical line test on a graph
Is this graph a function?→ No
A mapping diagram
Is this relation a function?→ No, x=2 has two arrows
Is the relation a function
Is this relation a function? {(5,5), (7,2), (5,6), (4,3)}→ No, x=5 is sent to two values
Questions about these worksheets
Yes. Every vertical line test sheet is free to print and free to download as a PDF. There is no account to make, no email to hand over and no limit on how many you take.
Yes. The answer key prints on a second page, and you can choose whether it shows each question beside its answer or just the answers in a list.
Yes. Print straight from the page, or download the PDF and print that. The sheet is laid out for paper rather than squeezed off a screen, so there is room to work under each question, and the answer key comes out on its own page.
Algebra 1 is usually taken around 8th or 9th grade, though schools vary and plenty of students meet it earlier or later. Pick the difficulty rather than the grade: the easy level suits a first lesson on it, the hard level suits review before a test.
Yes, as many as you like. The questions are built fresh each time rather than picked from a fixed set of files, so pressing Generate gives a new sheet. That is what you want for a second class, a retake, or two students sitting next to each other.
That is the closest comparison, and Kuta Software is good software. It is also paid software you install on a computer. These worksheets run in a browser tab for free, with no account and nothing to install. Like Kuta, the vertical line test questions are generated when you ask for them rather than pulled from a fixed set of files, so two classes never get the same sheet, and the answer key comes with it.
Yes. There are three levels, and you can tick more than one for a sheet that mixes them, in which case the questions come out easiest first. The harder levels are not just larger numbers: they ask for something the easy ones do not.
You pick from 3: the vertical line test on a graph, a mapping diagram and is the relation a function. Tick as many as you want and set how many of each, or let it spread them evenly.
Rejecting two inputs that share an output. That is still a function; only one input with two outputs breaks the rule, which is why a horizontal line passes and a vertical one does not.