x+y=16

is y a function of x

AAAaannndd the bot gets it wrong yet again!

No, for any value of x, there is only one value of y which lies on the line

y = 16-x

No, y is not a function of x. The equation x+y=16 is an equation of a straight line, which means that for any given value of x, there are an infinite number of possible values of y.