# Checking correctness of an inequality in two variables in table

How to check the correctness of an inequality in two variables entered by a student in a table?

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There are a few ways of doing this when it’s an equation, not an inequality.
a) parseEquation and use lhs rhs
b) parseEquation and difference functon
c) use a two variable function and check with a list

However, with an inequality these methods don’t work. I haven’t built one myself, but I imagine you would need to use parse and look for specific values in the latex that students are entering in the table. I hope this helps.

In the graph component:

``````f9a=parseEquation(Table.cellContent(9,2)).lhs
f9b=parseEquation(Table.cellContent(9,2)).rhs
function("f_9"): simpleFunction(f9a,"x","y")
``````

Takes students equation of an ellipse and makes it into a function that I check with in the graph: It’s slide 7 in this AB:

But it may be hard to follow. There is a lot going on in this activity beause it is an infinite problem set with like 6 different problem types. It might be easier for you to share whatever it is you are working on.

Hope this helps.