#Ax+By+C# is a generalized form (in fact the standard generalized form) for a linear equation
where #A, B, and C# are placeholders for constants (the #x# and #y# are variables).
The generalized form, #Ax+By+C#, includes equations such as #color(white)("XXXXX")##7x+3y=98# #color(white)("XXXXX")##(1)x+(-5)y=14# #color(white)("XXXXX")##9261x+83y=-7491# #color(white)("XXXXX")##color(white)("XXXXX")#any infinitely many others
By normal usage #A# should be an integer value which is not negative.