# Checking correctness - 2 variable linear inequalities

Hi! I’m trying to wrap my head around using computation layer. I’ve figured out a few things, but am getting stuck on one of my slides. I have students creating the graph of a linear inequality, and on the next slide I want them to enter 2 different points that are solutions to the inequality. I have figured out the coding to copy their graph onto the next slide, but cannot figure out how to check that the ordered pairs they enter are actually solutions to the inequality. I can always change it to multiple select, but I’d really like to be able to do some free response. Any help would be greatly appreciated!!!

Slide 7 is where I’m stuck.

There is nothing in the link to the activity. Is it marked private?

It says that it’s available to anyone with a link. I don’t think I had published it though, I think it was still in draft form, so I published it to see if that was the issue.

There are lots of ways to approach this. I redid your screen 8 to show one method. The idea is to use parseOrderedPair to get the student input, and then create a function for -3x+10 with simpleFunction. Then check if the y value is <= the value you get from evaluating -3x+10 at the point’s x-value.

I also showed how you can sink these different CL script values into numbers in the graph, which you can use to plot the points, and in this case, plot different kinds of points depending on correctness. Let me know if you have any questions about it.

Thank you so much!!! I’ll look over this today.