Is (2,3) (4,5) (2,8) a function?

With: label the vertices and all the elements needed. find x

Me! 50 points! why does when we come home, our door is unlocked and there is grease on the door knob, me solve this , and i don't know what category this goes under

F(n + 1) = f(n) – 8. if f(1) = 100, what is f(6)?