# Checking Points in systems of Inequalities

**URL:** <https://cl.desmos.com/t/checking-points-in-systems-of-inequalities/575>\
**Category:** Questions\
**Tags:** dashboard, validation, correctness\
**Created:** [September 21, 2019, 11:26pm UTC](https://cl.desmos.com/t/checking-points-in-systems-of-inequalities/575 "2019-09-21T23:26:29Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Matthew\_Moreno67](https://yyz1.discourse-cdn.com/flex031/user_avatar/cl.desmos.com/matthew_moreno67/32/362_2.png) [@Matthew\_Moreno67](https://cl.desmos.com/u/Matthew_Moreno67)\
**Post date:** [September 21, 2019, 11:26pm UTC](https://cl.desmos.com/t/checking-points-in-systems-of-inequalities/575/1 "2019-09-21T23:26:29Z")

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I’m trying to write this activity to take a graph and ask the students to plot points in the solution area. I have the ability to plot the points from a table but I would like to check for correctness so I can see the ✅ on the dashboard.

Any insight will be useful. (This is my first time using NumberList as well so sorry if this is a simple question)

> **[Systems of Inequalities • Activity by Matthew Moreno](https://classroom.amplify.com/activity/5d869ae117ef6e5958053f67)**
>
> by Matthew Moreno

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**Author:** ![JayChow](https://yyz1.discourse-cdn.com/flex031/user_avatar/cl.desmos.com/jaychow/32/1674_2.png) [@JayChow](https://cl.desmos.com/u/JayChow)\
**Post date:** [September 23, 2019, 4:05pm UTC](https://cl.desmos.com/t/checking-points-in-systems-of-inequalities/575/2 "2019-09-23T16:05:42Z")

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You can build the check in graph: [Desmos | Graphing Calculator](https://www.desmos.com/calculator/zww7szc2j3)

Then add a correct sink to the graph CL `correct: this.number("I_c") = 1`

Don’t forget to mark the table as readOnly