# Checking solutions of Linear Inequalities Systems

On screen 2, I am trying to get the shaded region of the system to appear, but only if they correctly identify an ordered pair in the region.
It will show up if I press the button 4 times like I asked it to, but not after the first condition.

https://teacher.desmos.com/activitybuilder/custom/61e896043838f81f8c8280b4

when- (when-) otherwise conditionals go through each step until something is true and output the corresponding result. If you don’t want the shading to show up at all until they find a correct ordered pair AND the button is pressed four times, then that should be in one line (add the second when condition as part of the first):

``````number("s_{howGraph}"):
when check3 and button1.timeSincePress>0 and button1.pressCount=4 1
otherwise 0
``````

I want it to show the shading on either condition. Like if their first guess ordered pair is correct, I want the shading to show up after they press the button. Then if they end up using all their guesses, the final press reveals the solution space. I just can’t get the first “when” to work.

I’ve tried so many different things inside of the graph and on the computation layer. I’m wondering if I what I want to happen is even possible at this point

X and Y as defined in the graph CL are going to be lists, meaning your checks I_1, I_2, and I are also lists. Since I isn’t a number, check3 will never be true. If you define X and Y as numbers instead of lists, it should work:

``````number(`X`): table2.cellNumericValue(1,1)
number(`Y`): table2.cellNumericValue(1,2)
``````

Side note: if you prefer students to use a single entry in coordinate notation, you can use a single math input instead of a table

``````myPair= parseOrderedPair(inputName.latex)
number(`X`): myPair.x
number(`Y`): myPair.y
``````

THANK YOU SO MUCH! I could literally cry this made me so happy

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