This type of question is perfect for Algebrator's Line Wizards, although it can also be nicely handled through doyourmath.com, but it is not the type of question which is intended for 'word problems'. 

To solve through doyourmath.com, replace 'x' with '3', then solve '3-y=9' and check whether y=1 [which it does not]. 

To explore this through Algebrator, open up the Wizards, expand 'Line' category and choose the wizard titled 'Evaluate a linear equation'.  Since 'x-y=9' solves to the points (3,-6) and (10,1), then the point (3,1) is not a solution of x-y=9. 

Of course, the question is ambiguous when "is (3,1) a solution of x-4=9" since "x-4" indicates y=4 but the pair (3,1) is for y=1... yea, the problem has a lot of issues. 

To help you clearly understand our desktop software and how appropriate it may be for your needs, please use one of the following links to obtain a free trial of the program:

Windows: https://www.softmath.com/tr/alg51win-tr-en.exe

Mac: https://www.softmath.com/tr/alg51mac-tr-en.dmg