# Function Notation Math Response: f(x)=2x

**URL:** <https://cl.desmos.com/t/function-notation-math-response-f-x-2x/7968>\
**Category:** Questions\
**Tags:** validation, correctness\
**Created:** [June 3, 2025, 10:00pm UTC](https://cl.desmos.com/t/function-notation-math-response-f-x-2x/7968 "2025-06-03T22:00:10Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![ASmith](https://yyz1.discourse-cdn.com/flex031/user_avatar/cl.desmos.com/asmith/32/360_2.png) [@ASmith](https://cl.desmos.com/u/ASmith)\
**Post date:** [June 3, 2025, 10:00pm UTC](https://cl.desmos.com/t/function-notation-math-response-f-x-2x/7968/1 "2025-06-03T22:00:10Z")

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Hello Amazing People!  
I’m looking for a way to check the function name in a Math Response. We want to check that the student is using the correct name of the function:  
If I ask you to write the slope intercept form of the function g, then the Math Response needs to begin with “g(x)=” and not “f(x)=” or “y=”

Any ideas? I know I can use simple function or xyline to check the slope and y-intercept. But I’m wondering if there’s a way to at least check what is on the left side of the equal sign if I can’t check the entire math response.

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**Author:** ![Daniel\_Wekselgreene](https://yyz1.discourse-cdn.com/flex031/user_avatar/cl.desmos.com/daniel_wekselgreene/32/1819_2.png) [@Daniel\_Wekselgreene](https://cl.desmos.com/u/Daniel_Wekselgreene)\
**Post date:** [June 4, 2025, 1:24am UTC](https://cl.desmos.com/t/function-notation-math-response-f-x-2x/7968/2 "2025-06-04T01:24:49Z")

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Sure - you can first parse the equation to extract the left and right sides, and then check that one of those sides matches g(x). Then you can use xyLine on the other side to check for correctness. Here is an example, let me know if you have questions. [checking for g(x)= • Activity Builder by Desmos Classroom](https://teacher.desmos.com/activitybuilder/custom/683f9e44a38b45780c05dd55?utm_campaign=share&utm_content=activity)

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**Author:** ![NTMDev](https://yyz1.discourse-cdn.com/flex031/user_avatar/cl.desmos.com/ntmdev/32/7141_2.png) [@NTMDev](https://cl.desmos.com/u/NTMDev)\
**Post date:** [June 4, 2025, 3:38am UTC](https://cl.desmos.com/t/function-notation-math-response-f-x-2x/7968/3 "2025-06-04T03:38:09Z")

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ah try using the `intialLatex` sink.

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<div class="post-metadata">

**Author:** ![ASmith](https://yyz1.discourse-cdn.com/flex031/user_avatar/cl.desmos.com/asmith/32/360_2.png) [@ASmith](https://cl.desmos.com/u/ASmith)\
**Post date:** [June 4, 2025, 12:02pm UTC](https://cl.desmos.com/t/function-notation-math-response-f-x-2x/7968/4 "2025-06-04T12:02:32Z")

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Thank you! This is perfect!

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**Author:** ![system](https://canada1.discourse-cdn.com/flex031/uploads/desmos/original/2X/f/f5bd144684474e9a2f333002cde9840e52c5dbd3.png) [@system](https://cl.desmos.com/u/system)\
**Post date:** [June 6, 2025, 12:02pm UTC](https://cl.desmos.com/t/function-notation-math-response-f-x-2x/7968/5 "2025-06-06T12:02:57Z")

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